Search Results

Search found 518 results on 21 pages for 'hooked'.

Page 21/21 | < Previous Page | 17 18 19 20 21 

• How to get IMediaControl.Run() to start a file playing with no delay

  - by MusiGenesis

  I am attempting to use DirectShow to play two AVI files consecutively (one after the other) so that there is no interruption in the audio or video when the player transitions from one file to the next. I have two custom controls on my form. Each one is pre-loaded with an AVI file, and before playback begins I set up all the DirectShow interfaces, set the video windows and resize them, call IMediaControl.Run(), then IMediaControl.Pause(), then IMediaSeeking.SetPositions to reset to frame 0, on both controls. On the form, you can see that both files are paused at their initial frames. I then call IMediaControl.Run() on the first control, and wait for it to complete before calling Run() on the second control. Initially, I hooked into the first video's EC_COMPLETE notification message, and used this to start the second. Thinking that this event might be slow to arrive (turns out it is, but for a weird reason), I tried two other approaches: Check the first video's current position inside a timer that goes off every second or so (using IMediaPosition.get_CurrentPosition). When the current position is within a second of the video's stop time (known in advance from IMediaPosition.get_StopTime), I go into a tight while loop and wait for the current position to equal the stop time, and then call Run() on the second video. Same as the first, except I replace the while loop with a call to timeSetEvent from winmm.dll, with a delay set so that it fires right when the first file is supposed to end. I use the callback to Run() the second file. Either of these two methods substantially cuts down the delay between the end of the first file and the beginning of the second, indicating that the EC_COMPLETE message doesn't arrive immediately after the file is complete (I also tried hooking the EC_SEGMENT_COMPLETE message, which is supposed to be used for looping within a file, but apparently nobody supports this - it never occurs on my machine, at least). Doing all of the above has cut the transition delay from as much as a second, down to a barely perceptible glitch; about a third of the time the files transition with no interruption at all, which suggests there's no fundamental reason I can't get this to work all the time. The slight delay is still unacceptable, unfortunately. I assume (and I could easily be wrong) that the remaining delay is due to a slight variable delay between the call to IMediaControl.Run() and when the video actually starts playing. Does anybody know anything I can do to eliminate this little lag? It would also help to be told this is fundamentally impossible for whatever reason, which wouldn't surprise me. I've never encountered a video player in Windows that doesn't have this problem, so it may not be doable. More info: the AVI files I'm playing are completely uncompressed (video and audio are uncompressed), so I don't think the lag is due to DirectShow's having to uncompress the video ahead of play start, although it may still buffer ahead as matter of course (and this may be the source of the problem). I would have though that starting play, pausing and then rewinding to the beginning would fix this. Also, the way I'm handling the transition is to actually have the second control underneath the first; when the first completes playing, I start the second and then call BringToFront on it, creating the appearance of a single video transitioning between the two originals. I don't think the glitch is due to this, because it works perfectly some of the time, and even if this were problematic, it wouldn't explain the matching audio glitch. Even more: I just tried starting the second video 30-50 milliseconds "early" and that seemed to eliminate even more of the gap, so I'm guessing that the lag in Run() is about that long. It appears to be variable, though, so this is still not where I need it to be.

  Read the article

• How to bind to the sum of two data bound values in WPF?

  - by Sheridan

  I have designed an analog clock control. It uses the stroke from two ellipses to represent an outer border and an inner border to the clock face. I have exposed properties in the UserControl that allow a user to alter the thickness of these two borders. The Ellipse.StrokeThickness properties are then bound to these UserControl properties. At the moment, I am binding the UserControl property for the outer border thickness to the margins of the inner elements so that they are not hidden when the border size is increased. <Ellipse Name="OuterBorder" Panel.ZIndex="1" StrokeThickness="{Binding OuterBorderThickness, ElementName=This}" Stroke="{StaticResource OuterBorderBrush}" /> <Ellipse Name="InnerBorder" Panel.ZIndex="5" StrokeThickness="{Binding InnerBorderThickness, ElementName=This}" Margin="{Binding OuterBorderThickness, ElementName=This}" Stroke="{StaticResource InnerBorderBrush}"> ... <Ellipse Name="Face" Panel.ZIndex="1" Margin="{Binding OuterBorderThickness, ElementName=This}" Fill="{StaticResource FaceBackgroundBrush}" /> ... The problem is that if the inner border thickness is increased, this does not affect the margins and so the hour ticks and numbers can become partially obscured or hidden. So what I really need is to be able to bind the margin properties of the inner controls to the sum of the inner and outer border thickness values (they are of type double). I have done this successfully using 'DataContext = this;', but am trying to rewrite the control without this as I hear it is not recommended. I also thought about using a converter and passing the second value as the ConverterParameter, but didn't know how to bind to the ConverterParameter. Any tips would be greatly appreciated. EDIT Thanks to Kent's suggestion, I've created a simple MultiConverter to add the input values and return the result. I've hooked the SAME multibinding with converter XAML to both a TextBlock.Text property and the TextBlock.Margin property to test it. <TextBlock> <TextBlock.Text> <MultiBinding Converter="{StaticResource SumConverter}" ConverterParameter="Add"> <Binding Path="OuterBorderThickness" ElementName="This" /> <Binding Path="InnerBorderThickness" ElementName="This" /> </MultiBinding> </TextBlock.Text> <TextBlock.Margin> <MultiBinding Converter="{StaticResource SumConverter}" ConverterParameter="Add"> <Binding Path="OuterBorderThickness" ElementName="This" /> <Binding Path="InnerBorderThickness" ElementName="This" /> </MultiBinding> </TextBlock.Margin> </TextBlock> I can see the correct value displayed in the TexBlock, but the Margin is not set. Any ideas? EDIT Interestingly, the Margin property can be bound to a data property of type double, but this does not seem to apply within a MultiBinding. As advised by Kent, I changed the Converter to return the value as a Thickness object and now it works. Thanks Kent.

  Read the article

• Using an alternate JSON Serializer in ASP.NET Web API

  - by Rick Strahl

  The new ASP.NET Web API that Microsoft released alongside MVC 4.0 Beta last week is a great framework for building REST and AJAX APIs. I've been working with it for quite a while now and I really like the way it works and the complete set of features it provides 'in the box'. It's about time that Microsoft gets a decent API for building generic HTTP endpoints into the framework. DataContractJsonSerializer sucks As nice as Web API's overall design is one thing still sucks: The built-in JSON Serialization uses the DataContractJsonSerializer which is just too limiting for many scenarios. The biggest issues I have with it are: No support for untyped values (object, dynamic, Anonymous Types) MS AJAX style Date Formatting Ugly serialization formats for types like Dictionaries To me the most serious issue is dealing with serialization of untyped objects. I have number of applications with AJAX front ends that dynamically reformat data from business objects to fit a specific message format that certain UI components require. The most common scenario I have there are IEnumerable query results from a database with fields from the result set rearranged to fit the sometimes unconventional formats required for the UI components (like jqGrid for example). Creating custom types to fit these messages seems like overkill and projections using Linq makes this much easier to code up. Alas DataContractJsonSerializer doesn't support it. Neither does DataContractSerializer for XML output for that matter. What this means is that you can't do stuff like this in Web API out of the box:public object GetAnonymousType() { return new { name = "Rick", company = "West Wind", entered= DateTime.Now }; } Basically anything that doesn't have an explicit type DataContractJsonSerializer will not let you return. FWIW, the same is true for XmlSerializer which also doesn't work with non-typed values for serialization. The example above is obviously contrived with a hardcoded object graph, but it's not uncommon to get dynamic values returned from queries that have anonymous types for their result projections. Apparently there's a good possibility that Microsoft will ship Json.NET as part of Web API RTM release.  Scott Hanselman confirmed this as a footnote in his JSON Dates post a few days ago. I've heard several other people from Microsoft confirm that Json.NET will be included and be the default JSON serializer, but no details yet in what capacity it will show up. Let's hope it ends up as the default in the box. Meanwhile this post will show you how you can use it today with the beta and get JSON that matches what you should see in the RTM version. What about JsonValue? To be fair Web API DOES include a new JsonValue/JsonObject/JsonArray type that allow you to address some of these scenarios. JsonValue is a new type in the System.Json assembly that can be used to build up an object graph based on a dictionary. It's actually a really cool implementation of a dynamic type that allows you to create an object graph and spit it out to JSON without having to create .NET type first. JsonValue can also receive a JSON string and parse it without having to actually load it into a .NET type (which is something that's been missing in the core framework). This is really useful if you get a JSON result from an arbitrary service and you don't want to explicitly create a mapping type for the data returned. For serialization you can create an object structure on the fly and pass it back as part of an Web API action method like this:public JsonValue GetJsonValue() { dynamic json = new JsonObject(); json.name = "Rick"; json.company = "West Wind"; json.entered = DateTime.Now; dynamic address = new JsonObject(); address.street = "32 Kaiea"; address.zip = "96779"; json.address = address; dynamic phones = new JsonArray(); json.phoneNumbers = phones; dynamic phone = new JsonObject(); phone.type = "Home"; phone.number = "808 123-1233"; phones.Add(phone); phone = new JsonObject(); phone.type = "Home"; phone.number = "808 123-1233"; phones.Add(phone); //var jsonString = json.ToString(); return json; } which produces the following output (formatted here for easier reading):{ name: "rick", company: "West Wind", entered: "2012-03-08T15:33:19.673-10:00", address: { street: "32 Kaiea", zip: "96779" }, phoneNumbers: [ { type: "Home", number: "808 123-1233" }, { type: "Mobile", number: "808 123-1234" }] } If you need to build a simple JSON type on the fly these types work great. But if you have an existing type - or worse a query result/list that's already formatted JsonValue et al. become a pain to work with. As far as I can see there's no way to just throw an object instance at JsonValue and have it convert into JsonValue dictionary. It's a manual process. Using alternate Serializers in Web API So, currently the default serializer in WebAPI is DataContractJsonSeriaizer and I don't like it. You may not either, but luckily you can swap the serializer fairly easily. If you'd rather use the JavaScriptSerializer built into System.Web.Extensions or Json.NET today, it's not too difficult to create a custom MediaTypeFormatter that uses these serializers and can replace or partially replace the native serializer. Here's a MediaTypeFormatter implementation using the ASP.NET JavaScriptSerializer:using System; using System.Net.Http.Formatting; using System.Threading.Tasks; using System.Web.Script.Serialization; using System.Json; using System.IO; namespace Westwind.Web.WebApi { public class JavaScriptSerializerFormatter : MediaTypeFormatter { public JavaScriptSerializerFormatter() { SupportedMediaTypes.Add(new System.Net.Http.Headers.MediaTypeHeaderValue("application/json")); } protected override bool CanWriteType(Type type) { // don't serialize JsonValue structure use default for that if (type == typeof(JsonValue) || type == typeof(JsonObject) || type== typeof(JsonArray) ) return false; return true; } protected override bool CanReadType(Type type) { if (type == typeof(IKeyValueModel)) return false; return true; } protected override System.Threading.Tasks.Taskobject OnReadFromStreamAsync(Type type, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext) { var task = Taskobject.Factory.StartNew(() = { var ser = new JavaScriptSerializer(); string json; using (var sr = new StreamReader(stream)) { json = sr.ReadToEnd(); sr.Close(); } object val = ser.Deserialize(json,type); return val; }); return task; } protected override System.Threading.Tasks.Task OnWriteToStreamAsync(Type type, object value, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext, System.Net.TransportContext transportContext) { var task = Task.Factory.StartNew( () = { var ser = new JavaScriptSerializer(); var json = ser.Serialize(value); byte[] buf = System.Text.Encoding.Default.GetBytes(json); stream.Write(buf,0,buf.Length); stream.Flush(); }); return task; } } } Formatter implementation is pretty simple: You override 4 methods to tell which types you can handle and then handle the input or output streams to create/parse the JSON data. Note that when creating output you want to take care to still allow JsonValue/JsonObject/JsonArray types to be handled by the default serializer so those objects serialize properly - if you let either JavaScriptSerializer or JSON.NET handle them they'd try to render the dictionaries which is very undesirable. If you'd rather use Json.NET here's the JSON.NET version of the formatter:// this code requires a reference to JSON.NET in your project #if true using System; using System.Net.Http.Formatting; using System.Threading.Tasks; using System.Web.Script.Serialization; using System.Json; using Newtonsoft.Json; using System.IO; using Newtonsoft.Json.Converters; namespace Westwind.Web.WebApi { public class JsonNetFormatter : MediaTypeFormatter { public JsonNetFormatter() { SupportedMediaTypes.Add(new System.Net.Http.Headers.MediaTypeHeaderValue("application/json")); } protected override bool CanWriteType(Type type) { // don't serialize JsonValue structure use default for that if (type == typeof(JsonValue) || type == typeof(JsonObject) || type == typeof(JsonArray)) return false; return true; } protected override bool CanReadType(Type type) { if (type == typeof(IKeyValueModel)) return false; return true; } protected override System.Threading.Tasks.Taskobject OnReadFromStreamAsync(Type type, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext) { var task = Taskobject.Factory.StartNew(() = { var settings = new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore, }; var sr = new StreamReader(stream); var jreader = new JsonTextReader(sr); var ser = new JsonSerializer(); ser.Converters.Add(new IsoDateTimeConverter()); object val = ser.Deserialize(jreader, type); return val; }); return task; } protected override System.Threading.Tasks.Task OnWriteToStreamAsync(Type type, object value, System.IO.Stream stream, System.Net.Http.Headers.HttpContentHeaders contentHeaders, FormatterContext formatterContext, System.Net.TransportContext transportContext) { var task = Task.Factory.StartNew( () = { var settings = new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore, }; string json = JsonConvert.SerializeObject(value, Formatting.Indented, new JsonConverter[1] { new IsoDateTimeConverter() } ); byte[] buf = System.Text.Encoding.Default.GetBytes(json); stream.Write(buf,0,buf.Length); stream.Flush(); }); return task; } } } #endif   One advantage of the Json.NET serializer is that you can specify a few options on how things are formatted and handled. You get null value handling and you can plug in the IsoDateTimeConverter which is nice to product proper ISO dates that I would expect any Json serializer to output these days. Hooking up the Formatters Once you've created the custom formatters you need to enable them for your Web API application. To do this use the GlobalConfiguration.Configuration object and add the formatter to the Formatters collection. Here's what this looks like hooked up from Application_Start in a Web project:protected void Application_Start(object sender, EventArgs e) { // Action based routing (used for RPC calls) RouteTable.Routes.MapHttpRoute( name: "StockApi", routeTemplate: "stocks/{action}/{symbol}", defaults: new { symbol = RouteParameter.Optional, controller = "StockApi" } ); // WebApi Configuration to hook up formatters and message handlers // optional RegisterApis(GlobalConfiguration.Configuration); } public static void RegisterApis(HttpConfiguration config) { // Add JavaScriptSerializer formatter instead - add at top to make default //config.Formatters.Insert(0, new JavaScriptSerializerFormatter()); // Add Json.net formatter - add at the top so it fires first! // This leaves the old one in place so JsonValue/JsonObject/JsonArray still are handled config.Formatters.Insert(0, new JsonNetFormatter()); } One thing to remember here is the GlobalConfiguration object which is Web API's static configuration instance. I think this thing is seriously misnamed given that GlobalConfiguration could stand for anything and so is hard to discover if you don't know what you're looking for. How about WebApiConfiguration or something more descriptive? Anyway, once you know what it is you can use the Formatters collection to insert your custom formatter. Note that I insert my formatter at the top of the list so it takes precedence over the default formatter. I also am not removing the old formatter because I still want JsonValue/JsonObject/JsonArray to be handled by the default serialization mechanism. Since they process in sequence and I exclude processing for these types JsonValue et al. still get properly serialized/deserialized. Summary Currently DataContractJsonSerializer in Web API is a pain, but at least we have the ability with relatively limited effort to replace the MediaTypeFormatter and plug in our own JSON serializer. This is useful for many scenarios - if you have existing client applications that used MVC JsonResult or ASP.NET AJAX results from ASMX AJAX services you can plug in the JavaScript serializer and get exactly the same serializer you used in the past so your results will be the same and don't potentially break clients. JSON serializers do vary a bit in how they serialize some of the more complex types (like Dictionaries and dates for example) and so if you're migrating it might be helpful to ensure your client code doesn't break when you switch to ASP.NET Web API. Going forward it looks like Microsoft is planning on plugging in Json.Net into Web API and make that the default. I think that's an awesome choice since Json.net has been around forever, is fast and easy to use and provides a ton of functionality as part of this great library. I just wish Microsoft would have figured this out sooner instead of now at the last minute integrating with it especially given that Json.Net has a similar set of lower level JSON objects JsonValue/JsonObject etc. which now will end up being duplicated by the native System.Json stuff. It's not like we don't already have enough confusion regarding which JSON serializer to use (JavaScriptSerializer, DataContractJsonSerializer, JsonValue/JsonObject/JsonArray and now Json.net). For years I've been using my own JSON serializer because the built in choices are both limited. However, with an official encorsement of Json.Net I'm happily moving on to use that in my applications. Let's see and hope Microsoft gets this right before ASP.NET Web API goes gold.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api  AJAX  ASP.NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

  Read the article

• UITableViewController and viewForHeaderInSection problems

  - by Fiona

  Hello, So I need your help please! I've created a UITableViewController: ContactDetailViewController. In IB in the nib file, I've added a view ahead of the table view and hooked it up to headerView - a UIView declared in the .h file. I've also created a view: CustomerHeaderView However when I run the code below, Its throwing an exception at the following line: headerView = [[UIView alloc] initWithNibName:@"ContactHeaderDetail" bundle:nil]; The error being thrown is: 2010-05-20 10:59:50.405 OnePageCRM[19620:20b] * -[UIView initWithNibName:bundle:]: unrecognized selector sent to instance 0x3ca4fa0 2010-05-20 10:59:50.406 OnePageCRM[19620:20b] Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '** -[UIView initWithNibName:bundle:]: unrecognized selector sent to instance 0x3ca4fa0' So any ideas anyone? Many thanks, Fiona // // ContactDetailViewController.m // OnePageCRM // // Created by Fiona Tighe on 19/05/2010. // Copyright 2010 __MyCompanyName__. All rights reserved. // #import "ContactDetailViewController.h" #import "DisplayInfoViewController.h" #import "ActionViewController.h" #define SectionHeaderHeigth 200 @implementation ContactDetailViewController @synthesize name; @synthesize date; @synthesize headerView; @synthesize nextAction; @synthesize nameLabel; @synthesize usernameLabel; @synthesize nextActionTextField; @synthesize dateLabel; @synthesize notesTableView; @synthesize contactInfoButton; @synthesize backgroundInfoButton; @synthesize actionDoneButton; - (void)viewDidLoad { [super viewDidLoad]; // Uncomment the following line to display an Edit button in the navigation bar for this view controller. // self.navigationItem.rightBarButtonItem = self.editButtonItem; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } #pragma mark Table view methods - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 2; } // Customize the number of rows in the table view. - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { int numOfRows; NSLog(@"section: %d", section); switch (section){ case 0: numOfRows = 0; break; case 1: numOfRows = 3; break; default: break; } return numOfRows; } - (UIView *) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section { if (section == 0){ headerView = [[UIView alloc] initWithNibName:@"ContactHeaderDetail" bundle:nil]; // headerView = [[UIView alloc] initWithNibName:@"ContactHeaderDetail" bundle:nil]; return headerView; }else{ return nil; } } - (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{ return SectionHeaderHeigth; } // Customize the appearance of table view cells. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } // Set up the cell... return cell; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { // Navigation logic may go here. Create and push another view controller. // AnotherViewController *anotherViewController = [[AnotherViewController alloc] initWithNibName:@"AnotherView" bundle:nil]; // [self.navigationController pushViewController:anotherViewController]; // [anotherViewController release]; } /* // Override to support conditional editing of the table view. - (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the specified item to be editable. return YES; } */ /* // Override to support editing the table view. - (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath { if (editingStyle == UITableViewCellEditingStyleDelete) { // Delete the row from the data source [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:YES]; } else if (editingStyle == UITableViewCellEditingStyleInsert) { // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view } } */ /* // Override to support rearranging the table view. - (void)tableView:(UITableView *)tableView moveRowAtIndexPath:(NSIndexPath *)fromIndexPath toIndexPath:(NSIndexPath *)toIndexPath { } */ /* // Override to support conditional rearranging of the table view. - (BOOL)tableView:(UITableView *)tableView canMoveRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the item to be re-orderable. return YES; } */ -(IBAction)displayContactInfo:(id)sender{ DisplayInfoViewController *divc = [[DisplayInfoViewController alloc] init]; divc.textView = self.nextAction; divc.title = @"Contact Info"; [self.navigationController pushViewController:divc animated:YES]; [divc release]; } -(IBAction)displayBackgroundInfo:(id)sender{ DisplayInfoViewController *divc = [[DisplayInfoViewController alloc] init]; divc.textView = self.nextAction; divc.title = @"Background Info"; [self.navigationController pushViewController:divc animated:YES]; [divc release]; } -(IBAction)actionDone:(id)sender{ ActionViewController *avc = [[ActionViewController alloc] init]; avc.title = @"Action"; avc.nextAction = self.nextAction; [self.navigationController pushViewController:avc animated:YES]; [avc release]; } - (void)dealloc { [name release]; [date release]; [nextAction release]; [nameLabel release]; [usernameLabel release]; [nextActionTextField release]; [dateLabel release]; [notesTableView release]; [contactInfoButton release]; [backgroundInfoButton release]; [actionDoneButton release]; [headerView release]; [super dealloc]; } @end

  Read the article

• A Communication System for XAML Applications

  - by psheriff

  In any application, you want to keep the coupling between any two or more objects as loose as possible. Coupling happens when one class contains a property that is used in another class, or uses another class in one of its methods. If you have this situation, then this is called strong or tight coupling. One popular design pattern to help with keeping objects loosely coupled is called the Mediator design pattern. The basics of this pattern are very simple; avoid one object directly talking to another object, and instead use another class to mediate between the two. As with most of my blog posts, the purpose is to introduce you to a simple approach to using a message broker, not all of the fine details. IPDSAMessageBroker Interface As with most implementations of a design pattern, you typically start with an interface or an abstract base class. In this particular instance, an Interface will work just fine. The interface for our Message Broker class just contains a single method “SendMessage” and one event “MessageReceived”. public delegate void MessageReceivedEventHandler( object sender, PDSAMessageBrokerEventArgs e); public interface IPDSAMessageBroker{  void SendMessage(PDSAMessageBrokerMessage msg);   event MessageReceivedEventHandler MessageReceived;} PDSAMessageBrokerMessage Class As you can see in the interface, the SendMessage method requires a type of PDSAMessageBrokerMessage to be passed to it. This class simply has a MessageName which is a ‘string’ type and a MessageBody property which is of the type ‘object’ so you can pass whatever you want in the body. You might pass a string in the body, or a complete Customer object. The MessageName property will help the receiver of the message know what is in the MessageBody property. public class PDSAMessageBrokerMessage{  public PDSAMessageBrokerMessage()  {  }   public PDSAMessageBrokerMessage(string name, object body)  {    MessageName = name;    MessageBody = body;  }   public string MessageName { get; set; }   public object MessageBody { get; set; }} PDSAMessageBrokerEventArgs Class As our message broker class will be raising an event that others can respond to, it is a good idea to create your own event argument class. This class will inherit from the System.EventArgs class and add a couple of additional properties. The properties are the MessageName and Message. The MessageName property is simply a string value. The Message property is a type of a PDSAMessageBrokerMessage class. public class PDSAMessageBrokerEventArgs : EventArgs{  public PDSAMessageBrokerEventArgs()  {  }   public PDSAMessageBrokerEventArgs(string name,     PDSAMessageBrokerMessage msg)  {    MessageName = name;    Message = msg;  }   public string MessageName { get; set; }   public PDSAMessageBrokerMessage Message { get; set; }} PDSAMessageBroker Class Now that you have an interface class and a class to pass a message through an event, it is time to create your actual PDSAMessageBroker class. This class implements the SendMessage method and will also create the event handler for the delegate created in your Interface. public class PDSAMessageBroker : IPDSAMessageBroker{  public void SendMessage(PDSAMessageBrokerMessage msg)  {    PDSAMessageBrokerEventArgs args;     args = new PDSAMessageBrokerEventArgs(      msg.MessageName, msg);     RaiseMessageReceived(args);  }   public event MessageReceivedEventHandler MessageReceived;   protected void RaiseMessageReceived(    PDSAMessageBrokerEventArgs e)  {    if (null != MessageReceived)      MessageReceived(this, e);  }} The SendMessage method will take a PDSAMessageBrokerMessage object as an argument. It then creates an instance of a PDSAMessageBrokerEventArgs class, passing to the constructor two items: the MessageName from the PDSAMessageBrokerMessage object and also the object itself. It may seem a little redundant to pass in the message name when that same message name is part of the message, but it does make consuming the event and checking for the message name a little cleaner – as you will see in the next section. Create a Global Message Broker In your WPF application, create an instance of this message broker class in the App class located in the App.xaml file. Create a public property in the App class and create a new instance of that class in the OnStartUp event procedure as shown in the following code: public partial class App : Application{  public PDSAMessageBroker MessageBroker { get; set; }   protected override void OnStartup(StartupEventArgs e)  {    base.OnStartup(e);     MessageBroker = new PDSAMessageBroker();  }} Sending and Receiving Messages Let’s assume you have a user control that you load into a control on your main window and you want to send a message from that user control to the main window. You might have the main window display a message box, or put a string into a status bar as shown in Figure 1. Figure 1: The main window can receive and send messages The first thing you do in the main window is to hook up an event procedure to the MessageReceived event of the global message broker. This is done in the constructor of the main window: public MainWindow(){  InitializeComponent();   (Application.Current as App).MessageBroker.     MessageReceived += new MessageReceivedEventHandler(       MessageBroker_MessageReceived);} One piece of code you might not be familiar with is accessing a property defined in the App class of your XAML application. Within the App.Xaml file is a class named App that inherits from the Application object. You access the global instance of this App class by using Application.Current. You cast Application.Current to ‘App’ prior to accessing any of the public properties or methods you defined in the App class. Thus, the code (Application.Current as App).MessageBroker, allows you to get at the MessageBroker property defined in the App class. In the MessageReceived event procedure in the main window (shown below) you can now check to see if the MessageName property of the PDSAMessageBrokerEventArgs is equal to “StatusBar” and if it is, then display the message body into the status bar text block control. void MessageBroker_MessageReceived(object sender,   PDSAMessageBrokerEventArgs e){  switch (e.MessageName)  {    case "StatusBar":      tbStatus.Text = e.Message.MessageBody.ToString();      break;  }} In the Page 1 user control’s Loaded event procedure you will send the message “StatusBar” through the global message broker to any listener using the following code: private void UserControl_Loaded(object sender,  RoutedEventArgs e){  // Send Status Message  (Application.Current as App).MessageBroker.    SendMessage(new PDSAMessageBrokerMessage("StatusBar",      "This is Page 1"));} Since the main window is listening for the message ‘StatusBar’, it will display the value “This is Page 1” in the status bar at the bottom of the main window. Sending a Message to a User Control The previous example sent a message from the user control to the main window. You can also send messages from the main window to any listener as well. Remember that the global message broker is really just a broadcaster to anyone who has hooked into the MessageReceived event. In the constructor of the user control named ucPage1 you can hook into the global message broker’s MessageReceived event. You can then listen for any messages that are sent to this control by using a similar switch-case structure like that in the main window. public ucPage1(){  InitializeComponent();   // Hook to the Global Message Broker  (Application.Current as App).MessageBroker.    MessageReceived += new MessageReceivedEventHandler(      MessageBroker_MessageReceived);} void MessageBroker_MessageReceived(object sender,  PDSAMessageBrokerEventArgs e){  // Look for messages intended for Page 1  switch (e.MessageName)  {    case "ForPage1":      MessageBox.Show(e.Message.MessageBody.ToString());      break;  }} Once the ucPage1 user control has been loaded into the main window you can then send a message using the following code: private void btnSendToPage1_Click(object sender,  RoutedEventArgs e){  PDSAMessageBrokerMessage arg =     new PDSAMessageBrokerMessage();   arg.MessageName = "ForPage1";  arg.MessageBody = "Message For Page 1";   // Send a message to Page 1  (Application.Current as App).MessageBroker.SendMessage(arg);} Since the MessageName matches what is in the ucPage1 MessageReceived event procedure, ucPage1 can do anything in response to that event. It is important to note that when the message gets sent it is sent to all MessageReceived event procedures, not just the one that is looking for a message called “ForPage1”. If the user control ucPage1 is not loaded and this message is broadcast, but no other code is listening for it, then it is simply ignored. Remove Event Handler In each class where you add an event handler to the MessageReceived event you need to make sure to remove those event handlers when you are done. Failure to do so can cause a strong reference to the class and thus not allow that object to be garbage collected. In each of your user control’s make sure in the Unloaded event to remove the event handler. private void UserControl_Unloaded(object sender, RoutedEventArgs e){  if (_MessageBroker != null)    _MessageBroker.MessageReceived -=         _MessageBroker_MessageReceived;} Problems with Message Brokering As with most “global” classes or classes that hook up events to other classes, garbage collection is something you need to consider. Just the simple act of hooking up an event procedure to a global event handler creates a reference between your user control and the message broker in the App class. This means that even when your user control is removed from your UI, the class will still be in memory because of the reference to the message broker. This can cause messages to still being handled even though the UI is not being displayed. It is up to you to make sure you remove those event handlers as discussed in the previous section. If you don’t, then the garbage collector cannot release those objects. Instead of using events to send messages from one object to another you might consider registering your objects with a central message broker. This message broker now becomes a collection class into which you pass an object and what messages that object wishes to receive. You do end up with the same problem however. You have to un-register your objects; otherwise they still stay in memory. To alleviate this problem you can look into using the WeakReference class as a method to store your objects so they can be garbage collected if need be. Discussing Weak References is beyond the scope of this post, but you can look this up on the web. Summary In this blog post you learned how to create a simple message broker system that will allow you to send messages from one object to another without having to reference objects directly. This does reduce the coupling between objects in your application. You do need to remember to get rid of any event handlers prior to your objects going out of scope or you run the risk of having memory leaks and events being called even though you can no longer access the object that is responding to that event. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “A Communication System for XAML Applications” from the drop down list.

  Read the article

• More Animation - Self Dismissing Dialogs

  - by Duncan Mills

  In my earlier articles on animation, I discussed various slide, grow and  flip transitions for items and containers.  In this article I want to discuss a fade animation and specifically the use of fades and auto-dismissal for informational dialogs.  If you use a Mac, you may be familiar with Growl as a notification system, and the nice way that messages that are informational just fade out after a few seconds. So in this blog entry I wanted to discuss how we could make an ADF popup behave in the same way. This can be an effective way of communicating information to the user without "getting in the way" with modal alerts. This of course, has been done before, but everything I've seen previously requires something like JQuery to be in the mix when we don't really need it to be.  The solution I've put together is nice and generic and will work with either <af:panelWindow> or <af:dialog> as a the child of the popup. In terms of usage it's pretty simple to use we  just need to ensure that the popup itself has clientComponent is set to true and includes the animation JavaScript (animateFadingPopup) on a popupOpened event: <af:popup id="pop1" clientComponent="true">   <af:panelWindow title="A Fading Message...">    ...  </af:panelWindow>   <af:clientListener method="animateFadingPopup" type="popupOpened"/> </af:popup>   The popup can be invoked in the normal way using showPopupBehavior or JavaScript, no special code is required there. As a further twist you can include an additional clientAttribute called preFadeDelay to define a delay before the fade itself starts (the default is 5 seconds) . To set the delay to just 2 seconds for example: <af:popup ...>   ...   <af:clientAttribute name="preFadeDelay" value="2"/>   <af:clientListener method="animateFadingPopup" type="popupOpened"/>  </af:popup> The Animation Styles  As before, we have a couple of CSS Styles which define the animation, I've put these into the skin in my case, and, as in the other articles, I've only defined the transitions for WebKit browsers (Chrome, Safari) at the moment. In this case, the fade is timed at 5 seconds in duration. .popupFadeReset {   opacity: 1; } .popupFadeAnimate {   opacity: 0;   -webkit-transition: opacity 5s ease-in-out; } As you can see here, we are achieving the fade by simply setting the CSS opacity property. The JavaScript The final part of the puzzle is, of course, the JavaScript, there are four functions, these are generic (apart from the Style names which, if you've changed above, you'll need to reflect here): The initial function invoked from the popupOpened event,  animateFadingPopup which starts a timer and provides the initial delay before we start to fade the popup. The function that applies the fade animation to the popup - initiatePopupFade. The callback function - closeFadedPopup used to reset the style class and correctly hide the popup so that it can be invoked again and again.   A utility function - findFadeContainer, which is responsible for locating the correct child component of the popup to actually apply the style to. Function - animateFadingPopup This function, as stated is the one hooked up to the popupOpened event via a clientListener. Because of when the code is called it does not actually matter how you launch the popup, or if the popup is re-used from multiple places. All usages will get the fade behavior. /**  * Client listener which will kick off the animation to fade the dialog and register  * a callback to correctly reset the popup once the animation is complete  * @param event  */ function animateFadingPopup(event) { var fadePopup = event.getSource();   var fadeCandidate = false;   //Ensure that the popup is initially Opaque   //This handles the situation where the user has dismissed   //the popup whilst it was in the process of fading   var fadeContainer = findFadeContainer(fadePopup);   if (fadeContainer != null) {     fadeCandidate = true;     fadeContainer.setStyleClass("popupFadeReset");   }   //Only continue if we can actually fade this popup   if (fadeCandidate) {   //See if a delay has been specified     var waitTimeSeconds = event.getSource().getProperty('preFadeDelay');     //Default to 5 seconds if not supplied     if (waitTimeSeconds == undefined) {     waitTimeSeconds = 5;     }     // Now call the fade after the specified time     var fadeFunction = function () {     initiatePopupFade(fadePopup);     };     var fadeDelayTimer = setTimeout(fadeFunction, (waitTimeSeconds * 1000));   } } The things to note about this function is the initial check that we have to do to ensure that the container is currently visible and reset it's style to ensure that it is.  This is to handle the situation where the popup has begun the fade, and yet the user has still explicitly dismissed the popup before it's complete and in doing so has prevented the callback function (described later) from executing. In this particular situation the initial display of the dialog will be (apparently) missing it's normal animation but at least it becomes visible to the user (and most users will probably not notice this difference in any case). You'll notice that the style that we apply to reset the  opacity - popupFadeReset, is not applied to the popup component itself but rather the dialog or panelWindow within it. More about that in the description of the next function findFadeContainer(). Finally, assuming that we have a suitable candidate for fading, a JavaScript  timer is started using the specified preFadeDelay wait time (or 5 seconds if that was not supplied). When this timer expires then the main animation styleclass will be applied using the initiatePopupFade() function Function - findFadeContainer As a component, the <af:popup> does not support styleClass attribute, so we can't apply the animation style directly.  Instead we have to look for the container within the popup which defines the window object that can have a style attached.  This is achieved by the following code: /**  * The thing we actually fade will be the only child  * of the popup assuming that this is a dialog or window  * @param popup  * @return the component, or null if this is not valid for fading  */ function findFadeContainer(popup) { var children = popup.getDescendantComponents();   var fadeContainer = children[0];   if (fadeContainer != undefined) {   var compType = fadeContainer.getComponentType();     if (compType == "oracle.adf.RichPanelWindow" || compType == "oracle.adf.RichDialog") {     return fadeContainer;     }   }   return null; }  So what we do here is to grab the first child component of the popup and check its type. Here I decided to limit the fade behaviour to only <af:dialog> and <af:panelWindow>. This was deliberate.  If  we apply the fade to say an <af:noteWindow> you would see the text inside the balloon fade, but the balloon itself would hang around until the fade animation was over and then hide.  It would of course be possible to make the code smarter to walk up the DOM tree to find the correct <div> to apply the style to in order to hide the whole balloon, however, that means that this JavaScript would then need to have knowledge of the generated DOM structure, something which may change from release to release, and certainly something to avoid. So, all in all, I think that this is an OK restriction and frankly it's windows and dialogs that I wanted to fade anyway, not balloons and menus. You could of course extend this technique and handle the other types should you really want to. One thing to note here is the selection of the first (children[0]) child of the popup. It does not matter if there are non-visible children such as clientListener before the <af:dialog> or <af:panelWindow> within the popup, they are not included in this array, so picking the first element in this way seems to be fine, no matter what the underlying ordering is within the JSF source.  If you wanted a super-robust version of the code you might want to iterate through the children array of the popup to check for the right type, again it's up to you.  Function -  initiatePopupFade  On to the actual fading. This is actually very simple and at it's heart, just the application of the popupFadeAnimate style to the correct component and then registering a callback to execute once the fade is done. /**  * Function which will kick off the animation to fade the dialog and register  * a callback to correctly reset the popup once the animation is complete  * @param popup the popup we are animating  */ function initiatePopupFade(popup) { //Only continue if the popup has not already been dismissed    if (popup.isPopupVisible()) {   //The skin styles that define the animation      var fadeoutAnimationStyle = "popupFadeAnimate";     var fadeAnimationResetStyle = "popupFadeReset";     var fadeContainer = findFadeContainer(popup);     if (fadeContainer != null) {     var fadeContainerReal = AdfAgent.AGENT.getElementById(fadeContainer.getClientId());       //Define the callback this will correctly reset the popup once it's disappeared       var fadeCallbackFunction = function (event) {       closeFadedPopup(popup, fadeContainer, fadeAnimationResetStyle);         event.target.removeEventListener("webkitTransitionEnd", fadeCallbackFunction);       };       //Initiate the fade       fadeContainer.setStyleClass(fadeoutAnimationStyle);       //Register the callback to execute once fade is done       fadeContainerReal.addEventListener("webkitTransitionEnd", fadeCallbackFunction, false);     }   } } I've added some extra checks here though. First of all we only start the whole process if the popup is still visible. It may be that the user has closed the popup before the delay timer has finished so there is no need to start animating in that case. Again we use the findFadeContainer() function to locate the correct component to apply the style to, and additionally we grab the DOM id that represents that container.  This physical ID is required for the registration of the callback function. The closeFadedPopup() call is then registered on the callback so as to correctly close the now transparent (but still there) popup. Function -  closeFadedPopup The final function just cleans things up: /**  * Callback function to correctly cancel and reset the style in the popup  * @param popup id of the popup so we can close it properly  * @param contatiner the window / dialog within the popup to actually style  * @param resetStyle the syle that sets the opacity back to solid  */ function closeFadedPopup(popup, container, resetStyle) { container.setStyleClass(resetStyle);   popup.cancel(); }  First of all we reset the style to make the popup contents opaque again and then we cancel the popup.  This will ensure that any of your user code that is waiting for a popup cancelled event will actually get the event, additionally if you have done this as a modal window / dialog it will ensure that the glasspane is dismissed and you can interact with the UI again.  What's Next? There are several ways in which this technique could be used, I've been working on a popup here, but you could apply the same approach to in-line messages. As this code (in the popup case) is generic it will make s pretty nice declarative component and maybe, if I get time, I'll look at constructing a formal Growl component using a combination of this technique, and active data push. Also, I'm sure the above code can be improved a little too.  Specifically things like registering a popup cancelled listener to handle the style reset so that we don't loose the subtle animation that takes place when the popup is opened in that situation where the user has closed the in-fade dialog.

  Read the article

• How to Run Low-Cost Minecraft on a Raspberry Pi for Block Building on the Cheap

  - by Jason Fitzpatrick

  We’ve shown you how to run your own blocktastic personal Minecraft server on a Windows/OSX box, but what if you crave something lighter weight, more energy efficient, and always ready for your friends? Read on as we turn a tiny Raspberry Pi machine into a low-cost Minecraft server you can leave on 24/7 for around a penny a day. Why Do I Want to Do This? There’s two aspects to this tutorial, running your own Minecraft server and specifically running that Minecraft server on a Raspberry Pi. Why would you want to run your own Minecraft server? It’s a really great way to extend and build upon the Minecraft play experience. You can leave the server running when you’re not playing so friends and family can join and continue building your world. You can mess around with game variables and introduce mods in a way that isn’t possible when you’re playing the stand-alone game. It also gives you the kind of control over your multiplayer experience that using public servers doesn’t, without incurring the cost of hosting a private server on a remote host. While running a Minecraft server on its own is appealing enough to a dedicated Minecraft fan, running it on the Raspberry Pi is even more appealing. The tiny little Pi uses so little resources that you can leave your Minecraft server running 24/7 for a couple bucks a year. Aside from the initial cost outlay of the Pi, an SD card, and a little bit of time setting it up, you’ll have an always-on Minecraft server at a monthly cost of around one gumball. What Do I Need? For this tutorial you’ll need a mix of hardware and software tools; aside from the actual Raspberry Pi and SD card, everything is free. 1 Raspberry Pi (preferably a 512MB model) 1 4GB+ SD card This tutorial assumes that you have already familiarized yourself with the Raspberry Pi and have installed a copy of the Debian-derivative Raspbian on the device. If you have not got your Pi up and running yet, don’t worry! Check out our guide, The HTG Guide to Getting Started with Raspberry Pi, to get up to speed. Optimizing Raspbian for the Minecraft Server Unlike other builds we’ve shared where you can layer multiple projects over one another (e.g. the Pi is more than powerful enough to serve as a weather/email indicator and a Google Cloud Print server at the same time) running a Minecraft server is a pretty intense operation for the little Pi and we’d strongly recommend dedicating the entire Pi to the process. Minecraft seems like a simple game, with all its blocky-ness and what not, but it’s actually a pretty complex game beneath the simple skin and required a lot of processing power. As such, we’re going to tweak the configuration file and other settings to optimize Rasbian for the job. The first thing you’ll need to do is dig into the Raspi-Config application to make a few minor changes. If you’re installing Raspbian fresh, wait for the last step (which is the Raspi-Config), if you already installed it, head to the terminal and type in “sudo raspi-config” to launch it again. One of the first and most important things we need to attend to is cranking up the overclock setting. We need all the power we can get to make our Minecraft experience enjoyable. In Raspi-Config, select option number 7 “Overclock”. Be prepared for some stern warnings about overclocking, but rest easy knowing that overclocking is directly supported by the Raspberry Pi foundation and has been included in the configuration options since late 2012. Once you’re in the actual selection screen, select “Turbo 1000MhHz”. Again, you’ll be warned that the degree of overclocking you’ve selected carries risks (specifically, potential corruption of the SD card, but no risk of actual hardware damage). Click OK and wait for the device to reset. Next, make sure you’re set to boot to the command prompt, not the desktop. Select number 3 “Enable Boot to Desktop/Scratch”  and make sure “Console Text console” is selected. Back at the Raspi-Config menu, select number 8 “Advanced Options’. There are two critical changes we need to make in here and one option change. First, the critical changes. Select A3 “Memory Split”: Change the amount of memory available to the GPU to 16MB (down from the default 64MB). Our Minecraft server is going to ruin in a GUI-less environment; there’s no reason to allocate any more than the bare minimum to the GPU. After selecting the GPU memory, you’ll be returned to the main menu. Select “Advanced Options” again and then select A4 “SSH”. Within the sub-menu, enable SSH. There is very little reason to keep this Pi connected to a monitor and keyboard, by enabling SSH we can remotely access the machine from anywhere on the network. Finally (and optionally) return again to the “Advanced Options” menu and select A2 “Hostname”. Here you can change your hostname from “raspberrypi” to a more fitting Minecraft name. We opted for the highly creative hostname “minecraft”, but feel free to spice it up a bit with whatever you feel like: creepertown, minecraft4life, or miner-box are all great minecraft server names. That’s it for the Raspbian configuration tab down to the bottom of the main screen and select “Finish” to reboot. After rebooting you can now SSH into your terminal, or continue working from the keyboard hooked up to your Pi (we strongly recommend switching over to SSH as it allows you to easily cut and paste the commands). If you’ve never used SSH before, check out how to use PuTTY with your Pi here. Installing Java on the Pi The Minecraft server runs on Java, so the first thing we need to do on our freshly configured Pi is install it. Log into your Pi via SSH and then, at the command prompt, enter the following command to make a directory for the installation: sudo mkdir /java/ Now we need to download the newest version of Java. At the time of this publication the newest release is the OCT 2013 update and the link/filename we use will reflect that. Please check for a more current version of the Linux ARMv6/7 Java release on the Java download page and update the link/filename accordingly when following our instructions. At the command prompt, enter the following command: sudo wget --no-check-certificate http://www.java.net/download/jdk8/archive/b111/binaries/jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz Once the download has finished successfully, enter the following command: sudo tar zxvf jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz -C /opt/ Fun fact: the /opt/ directory name scheme is a remnant of early Unix design wherein the /opt/ directory was for “optional” software installed after the main operating system; it was the /Program Files/ of the Unix world. After the file has finished extracting, enter: sudo /opt/jdk1.8.0/bin/java -version This command will return the version number of your new Java installation like so: java version "1.8.0-ea" Java(TM) SE Runtime Environment (build 1.8.0-ea-b111) Java HotSpot(TM) Client VM (build 25.0-b53, mixed mode) If you don’t see the above printout (or a variation thereof if you’re using a newer version of Java), try to extract the archive again. If you do see the readout, enter the following command to tidy up after yourself: sudo rm jdk-8-ea-b111-linux-arm-vfp-hflt-09_oct_2013.tar.gz At this point Java is installed and we’re ready to move onto installing our Minecraft server! Installing and Configuring the Minecraft Server Now that we have a foundation for our Minecraft server, it’s time to install the part that matter. We’ll be using SpigotMC a lightweight and stable Minecraft server build that works wonderfully on the Pi. First, grab a copy of the the code with the following command: sudo wget http://ci.md-5.net/job/Spigot/lastSuccessfulBuild/artifact/Spigot-Server/target/spigot.jar This link should remain stable over time, as it points directly to the most current stable release of Spigot, but if you have any issues you can always reference the SpigotMC download page here. After the download finishes successfully, enter the following command: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Note: if you’re running the command on a 256MB Pi change the 256 and 496 in the above command to 128 and 256, respectively. Your server will launch and a flurry of on-screen activity will follow. Be prepared to wait around 3-6 minutes or so for the process of setting up the server and generating the map to finish. Future startups will take much less time, around 20-30 seconds. Note: If at any point during the configuration or play process things get really weird (e.g. your new Minecraft server freaks out and starts spawning you in the Nether and killing you instantly), use the “stop” command at the command prompt to gracefully shutdown the server and let you restart and troubleshoot it. After the process has finished, head over to the computer you normally play Minecraft on, fire it up, and click on Multiplayer. You should see your server: If your world doesn’t popup immediately during the network scan, hit the Add button and manually enter the address of your Pi. Once you connect to the server, you’ll see the status change in the server status window: According to the server, we’re in game. According to the actual Minecraft app, we’re also in game but it’s the middle of the night in survival mode: Boo! Spawning in the dead of night, weaponless and without shelter is no way to start things. No worries though, we need to do some more configuration; no time to sit around and get shot at by skeletons. Besides, if you try and play it without some configuration tweaks first, you’ll likely find it quite unstable. We’re just here to confirm the server is up, running, and accepting incoming connections. Once we’ve confirmed the server is running and connectable (albeit not very playable yet), it’s time to shut down the server. Via the server console, enter the command “stop” to shut everything down. When you’re returned to the command prompt, enter the following command: sudo nano server.properties When the configuration file opens up, make the following changes (or just cut and paste our config file minus the first two lines with the name and date stamp): #Minecraft server properties #Thu Oct 17 22:53:51 UTC 2013 generator-settings= #Default is true, toggle to false allow-nether=false level-name=world enable-query=false allow-flight=false server-port=25565 level-type=DEFAULT enable-rcon=false force-gamemode=false level-seed= server-ip= max-build-height=256 spawn-npcs=true white-list=false spawn-animals=true texture-pack= snooper-enabled=true hardcore=false online-mode=true pvp=true difficulty=1 player-idle-timeout=0 gamemode=0 #Default 20; you only need to lower this if you're running #a public server and worried about loads. max-players=20 spawn-monsters=true #Default is 10, 3-5 ideal for Pi view-distance=5 generate-structures=true spawn-protection=16 motd=A Minecraft Server In the server status window, seen through your SSH connection to the pi, enter the following command to give yourself operator status on your Minecraft server (so that you can use more powerful commands in game, without always returning to the server status window). op [your minecraft nickname] At this point things are looking better but we still have a little tweaking to do before the server is really enjoyable. To that end, let’s install some plugins. The first plugin, and the one you should install above all others, is NoSpawnChunks. To install the plugin, first visit the NoSpawnChunks webpage and grab the download link for the most current version. As of this writing the current release is v0.3. Back at the command prompt (the command prompt of your Pi, not the server console–if your server is still active shut it down) enter the following commands: cd /home/pi/plugins sudo wget http://dev.bukkit.org/media/files/586/974/NoSpawnChunks.jar Next, visit the ClearLag plugin page, and grab the latest link (as of this tutorial, it’s v2.6.0). Enter the following at the command prompt: sudo wget http://dev.bukkit.org/media/files/743/213/Clearlag.jar Because the files aren’t compressed in a .ZIP or similar container, that’s all there is to it: the plugins are parked in the plugin directory. (Remember this for future plugin downloads, the file needs to be whateverplugin.jar, so if it’s compressed you need to uncompress it in the plugin directory.) Resart the server: sudo /opt/jdk1.8.0/bin/java -Xms256M -Xmx496M -jar /home/pi/spigot.jar nogui Be prepared for a slightly longer startup time (closer to the 3-6 minutes and much longer than the 30 seconds you just experienced) as the plugins affect the world map and need a minute to massage everything. After the spawn process finishes, type the following at the server console: plugins This lists all the plugins currently active on the server. You should see something like this: If the plugins aren’t loaded, you may need to stop and restart the server. After confirming your plugins are loaded, go ahead and join the game. You should notice significantly snappier play. In addition, you’ll get occasional messages from the plugins indicating they are active, as seen below: At this point Java is installed, the server is installed, and we’ve tweaked our settings for for the Pi.  It’s time to start building with friends!     

  Read the article

• A jQuery Plug-in to monitor Html Element CSS Changes

  - by Rick Strahl

  Here's a scenario I've run into on a few occasions: I need to be able to monitor certain CSS properties on an HTML element and know when that CSS element changes. The need for this arose out of wanting to build generic components that could 'attach' themselves to other objects and monitor changes on the ‘parent’ object so the dependent object can adjust itself accordingly. What I wanted to create is a jQuery plug-in that allows me to specify a list of CSS properties to monitor and have a function fire in response to any change to any of those CSS properties. The result are the .watch() and .unwatch() jQuery plug-ins. Here’s a simple example page of this plug-in that demonstrates tracking changes to an element being moved with draggable and closable behavior: http://www.west-wind.com/WestWindWebToolkit/samples/Ajax/jQueryPluginSamples/WatcherPlugin.htm Try it with different browsers – IE and FireFox use the DOM event handlers and Chrome, Safari and Opera use setInterval handlers to manage this behavior. It should work in all of them but all but IE and FireFox will show a bit of lag between the changes in the main element and the shadow. The relevant HTML for this example is this fragment of a main <div> (#notebox) and an element that is to mimic a shadow (#shadow). <div class="containercontent"> <div id="notebox" style="width: 200px; height: 150px;position: absolute; z-index: 20; padding: 20px; background-color: lightsteelblue;"> Go ahead drag me around and close me! </div> <div id="shadow" style="background-color: Gray; z-index: 19;position:absolute;display: none;"> </div> </div> The watcher plug in is then applied to the main <div> and shadow in sync with the following plug-in code: <script type="text/javascript"> $(document).ready(function () { var counter = 0; $("#notebox").watch("top,left,height,width,display,opacity", function (data, i) { var el = $(this); var sh = $("#shadow"); var propChanged = data.props[i]; var valChanged = data.vals[i]; counter++; showStatus("Prop: " + propChanged + " value: " + valChanged + " " + counter); var pos = el.position(); var w = el.outerWidth(); var h = el.outerHeight(); sh.css({ width: w, height: h, left: pos.left + 5, top: pos.top + 5, display: el.css("display"), opacity: el.css("opacity") }); }) .draggable() .closable() .css("left", 10); }); </script> When you run this page as you drag the #notebox element the #shadow element will maintain and stay pinned underneath the #notebox element effectively keeping the shadow attached to the main element. Likewise, if you hide or fadeOut() the #notebox element the shadow will also go away – show the #notebox element and the shadow also re-appears because we are assigning the display property from the parent on the shadow. Note we’re attaching the .watch() plug-in to the #notebox element and have it fire whenever top,left,height,width,opacity or display CSS properties are changed. The passed data element contains a props[] and vals[] array that holds the properties monitored and their current values. An index passed as the second parm tells you which property has changed and what its current value is (propChanged/valChanged in the code above). The rest of the watcher handler code then deals with figuring out the main element’s position and recalculating and setting the shadow’s position using the jQuery .css() function. Note that this is just an example to demonstrate the watch() behavior here – this is not the best way to create a shadow. If you’re interested in a more efficient and cleaner way to handle shadows with a plug-in check out the .shadow() plug-in in ww.jquery.js (code search for fn.shadow) which uses native CSS features when available but falls back to a tracked shadow element on browsers that don’t support it, which is how this watch() plug-in came about in the first place :-) How does it work? The plug-in works by letting the user specify a list of properties to monitor as a comma delimited string and a handler function: el.watch("top,left,height,width,display,opacity", function (data, i) {}, 100, id) You can also specify an interval (if no DOM event monitoring isn’t available in the browser) and an ID that identifies the event handler uniquely. The watch plug-in works by hooking up to DOMAttrModified in FireFox, to onPropertyChanged in Internet Explorer, or by using a timer with setInterval to handle the detection of changes for other browsers. Unfortunately WebKit doesn’t support DOMAttrModified consistently at the moment so Safari and Chrome currently have to use the slower setInterval mechanism. In response to a changed property (or a setInterval timer hit) a JavaScript handler is fired which then runs through all the properties monitored and determines if and which one has changed. The DOM events fire on all property/style changes so the intermediate plug-in handler filters only those hits we’re interested in. If one of our monitored properties has changed the specified event handler function is called along with a data object and an index that identifies the property that’s changed in the data.props/data.vals arrays. The jQuery plugin to implement this functionality looks like this: (function($){ $.fn.watch = function (props, func, interval, id) { /// <summary> /// Allows you to monitor changes in a specific /// CSS property of an element by polling the value. /// when the value changes a function is called. /// The function called is called in the context /// of the selected element (ie. this) /// </summary> /// <param name="prop" type="String">CSS Properties to watch sep. by commas</param> /// <param name="func" type="Function"> /// Function called when the value has changed. /// </param> /// <param name="interval" type="Number"> /// Optional interval for browsers that don't support DOMAttrModified or propertychange events. /// Determines the interval used for setInterval calls. /// </param> /// <param name="id" type="String">A unique ID that identifies this watch instance on this element</param> /// <returns type="jQuery" /> if (!interval) interval = 100; if (!id) id = "_watcher"; return this.each(function () { var _t = this; var el$ = $(this); var fnc = function () { __watcher.call(_t, id) }; var data = { id: id, props: props.split(","), vals: [props.split(",").length], func: func, fnc: fnc, origProps: props, interval: interval, intervalId: null }; // store initial props and values $.each(data.props, function (i) { data.vals[i] = el$.css(data.props[i]); }); el$.data(id, data); hookChange(el$, id, data); }); function hookChange(el$, id, data) { el$.each(function () { var el = $(this); if (typeof (el.get(0).onpropertychange) == "object") el.bind("propertychange." + id, data.fnc); else if ($.browser.mozilla) el.bind("DOMAttrModified." + id, data.fnc); else data.intervalId = setInterval(data.fnc, interval); }); } function __watcher(id) { var el$ = $(this); var w = el$.data(id); if (!w) return; var _t = this; if (!w.func) return; // must unbind or else unwanted recursion may occur el$.unwatch(id); var changed = false; var i = 0; for (i; i < w.props.length; i++) { var newVal = el$.css(w.props[i]); if (w.vals[i] != newVal) { w.vals[i] = newVal; changed = true; break; } } if (changed) w.func.call(_t, w, i); // rebind event hookChange(el$, id, w); } } $.fn.unwatch = function (id) { this.each(function () { var el = $(this); var data = el.data(id); try { if (typeof (this.onpropertychange) == "object") el.unbind("propertychange." + id, data.fnc); else if ($.browser.mozilla) el.unbind("DOMAttrModified." + id, data.fnc); else clearInterval(data.intervalId); } // ignore if element was already unbound catch (e) { } }); return this; } })(jQuery); Note that there’s a corresponding .unwatch() plug-in that can be used to stop monitoring properties. The ID parameter is optional both on watch() and unwatch() – a standard name is used if you don’t specify one, but it’s a good idea to use unique names for each element watched to avoid overlap in event ids especially if you’re monitoring many elements. The syntax is: $.fn.watch = function(props, func, interval, id) props A comma delimited list of CSS style properties that are to be watched for changes. If any of the specified properties changes the function specified in the second parameter is fired. func The function fired in response to a changed styles. Receives this as the element changed and an object parameter that represents the watched properties and their respective values. The first parameter is passed in this structure: { id: watcherId, props: [], vals: [], func: thisFunc, fnc: internalHandler, origProps: strPropertyListOnWatcher }; A second parameter is the index of the changed property so data.props[i] or data.vals[i] gets the property and changed value. interval The interval for setInterval() for those browsers that don't support property watching in the DOM. In milliseconds. id An optional id that identifies this watcher. Required only if multiple watchers might be hooked up to the same element. The default is _watcher if not specified. It’s been a Journey I started building this plug-in about two years ago and had to make many modifications to it in response to changes in jQuery and also in browser behaviors. I think the latest round of changes made should make this plug-in fairly future proof going forward (although I hope there will be better cross-browser change event notifications in the future). One of the big problems I ran into had to do with recursive change notifications – it looks like starting with jQuery 1.44 and later, jQuery internally modifies element properties on some calls to some .css()  property retrievals and things like outerHeight/Width(). In IE this would cause nasty lock up issues at times. In response to this I changed the code to unbind the events when the handler function is called and then rebind when it exits. This also makes user code less prone to stack overflow recursion as you can actually change properties on the base element. It also means though that if you change one of the monitors properties in the handler the watch() handler won’t fire in response – you need to resort to a setTimeout() call instead to force the code to run outside of the handler: $("#notebox") el.watch("top,left,height,width,display,opacity", function (data, i) { var el = $(this); … // this makes el changes work setTimeout(function () { el.css("top", 10) },10); }) Since I’ve built this component I’ve had a lot of good uses for it. The .shadow() fallback functionality is one of them. Resources The watch() plug-in is part of ww.jquery.js and the West Wind West Wind Web Toolkit. You’re free to use this code here or the code from the toolkit. West Wind Web Toolkit Latest version of ww.jquery.js (search for fn.watch) watch plug-in documentation © Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  JavaScript  jQuery  

  Read the article

• Prepping a conference

  - by Laurent Bugnion

  I have had the chance to talk at many conferences these past few years, and came up with a way to prepare them which works really well for me. Most importantly, it would make it quite easy to overcome an emergency (for example if my laptop would suddenly lose data). The whole code as well as the slides and other documents are in the cloud. I also use source control for my demos, so that I always have the latest and the greatest, but also a history of changes I made to my demos. Finally I have a system of code snippets which works great, and I often had very positive remarks from the audience regarding that. Putting everything in the cloud The one thing I used to be the most scared of was a sudden crash of my laptop, and being unable to restore in time for a conference. Most conferences ask speakers to send slides a few days (or weeks…) in advance, but let's face it, we all have last minute changes to our talks and I always come in the conference with updated slides that I pass to the management team. The answer to that dilemma used to be working off memory sticks, and that worked not bad. However last year I started putting all the documents relating to a conference in a DropBox folder, and that works great too. Obviously DropBox works only if you have connectivity, so if I for instance update slides while on an international flight, I cannot save to the cloud. The obvious answer to that is to backup everything on a memory stick… but I have to admit, I have been trusting my luck and working off my laptop HD and then synching everything to the cloud after landing. Of course on some US national flights you get WiFi on board, so in that case it is even simpler :) Usually after the conference is done, I remove the files from DropBox and copy them to their "final destination". They are backed up from there to BackBlaze, the great online backup service I am using routinely (I currently have about 90GB of data in BackBlaze). Outlining the presentations I like to have a written outline of my presentations written somewhere. I keep it simple, just write the various sections of the presentation with timing. I guess it is a remnant of the time when I was a private pilot, and using checklists for flight preparation. For example: Demo about designability 15' (0:37) Switch to Blend Open MainPage.xaml Create a DataTemplate ... Here I can immediately see during the presentation if I am taking too much time for my demo (0:37 is where I need to be when I am done with this section of the presentation, and 15' is the time that this particular section takes). I keep these sections reasonable, I don't detail every step of the preparation. Typically I have one such section for every 10-15 minutes of my talks. Yes, I am timing my presentations. I keep adjusting these numbers when I rehearse, and this really helps to feel more confident during the presentations. This is especially important for presentations that are long, like my MIX11 demo which clocked at 57 minutes (I had a lot of stuff to show…). Such presentations are risky, because if anything goes wrong, you will have to cut stuff, so the answer to that is: Rehearse, rehearse and when you're done rehearsing, rehearse a little more. I also have a "Preparation" section where I outline what I need to do before a presentation. For instance: Preparation Reboot in VHD Make sure MSN and Twitter are not running. Open VS10 and load demo Open Blend and load demo Run the WP7 emulator ... I typically start preparing my laptop an hour before the talk, starting everything I need to start and then putting my laptop to sleep. Saving and printing the outline, Timing Printing is a real problem because it is really hard to find a printer at most conference venues, and also quite hard in hotels. To solve that, I simply write everything in OneNote (synched to the cloud, now you start to know what I like ;) and then I print it to a PDF (I use CutePDFWriter) that I save to my Kindle. During the presentation, I read the outline off the Kindle (I mostly just need a quick check to see how I am timing). For timing during the presentation, I use the free tool ChronoGPS on my Windows Phone 7, but of course any phone these days has a clock/chrono application. In some conferences, they even have timers that the presenters can see, but they tend to count down and I prefer to count up… so I just use my own :) Source control for demos For demos, I create a separate folder and use Mercurial as source control. Mercurial has the huge advantage (over SVN or TFS) to work offline too, so I can commit while on a plane, and all the history is saved. Then when I have connectivity I push everything to the cloud (I am using the fantastic Trunksapp.com for my private repositories). Here too the obvious downside is the risk of losing my last changes if my laptop crashes before I can push to the cloud, and here too the obvious answer would be to work from a memory stick… though I have to admit I didn't do that lately (except when I was writing Silverlight 4 Unleashed, where I was really paranoid…) And code snippets? I am one of these presenters who hates to type in front of an audience. I can type really fast (writing two books has this advantage, it really teaches you to touch type and be fast at it) but in the context of an audience, on a stage where it is often damn cold (an issue I had a lot in past conferences, air conditioning can freeze your fingers and make it really hard to type), it doesn't work as well. I don't know for you, but I really dislike seeing a presentation where the speaker uses the backspace key more often than others ;) To solve that, I like to have my code ready in snippets, and drag them to the screen. Then I can spend time explaining each code snippet, while highlighting portions of the code (always highlight what you talk about, the audience often doesn't even see the cursor and doesn't know where you are on the screen!) Over the years I have used various solutions for code snippets, and now I have one which works really well… if you take a few precautions! I use the Visual Studio Toolbox. Preparing the code snippets You can store code snippets in the Toolbox for anything, XAML, C# etc. I arrange the snippets in the order in which I need them, which is a great way to remember what comes next in the presentation. I also separate them by topic, to make it easier to find them, for example when I switch to the slides and then back to the code. Remember that no matter how experienced you are, you will feel more nervous on stage than while you are preparing, so any way to make it easier for you is going to be beneficial to the audience. To store a code snippet, I do the following: Open the final demo that you want to show to the audience in Visual Studio. In your code, select a snippet of code that you want to explain in particular. Make sure that the Visual Studio Toolbox is open (menu View, Toolbox or Ctrl-Alt-X). Drag the selected snippet from the code window to the toolbox. (if needed) drag the snippet to the correct location (for example between two other code snippets so that you can access it as you speak through the demo). Right click on the snippet and select Rename Item from the context menu. Select a meaningful name. For me I use the following conventions: If it is a method, I use the method's name. If it is not a whole method, I use a descriptive name. If it is the content of a method (i.e. the body only, without the method's signature), I use "-> MethodName". This reminds me during the presentation that this is only the body, and that I need to insert that into an existing signature. This is the case, for instance, when I use Visual Studio to automatically generate the members of an interface’s implementation; then I only need to insert my snippet inside the generated method body. Saving the snippets This is the most important!! It happened to me a few times that VS10 lost its settings. When that happens, the snippets are lost too! Yeah that really sucks, especially (as it happened once) when this is the case about an hour before a talk… Stress and sweat follows, not good conditions to start a talk in front of an audience believe me. Thankfully, saving snippets is really easy with the following steps: Select the menu Tools, Import and Export Settings. Select Export selected environment settings and press Next. Uncheck All Settings. Then expand General Settings and select Toolbox (only!). Press Next. Select your source control folder and save under a meaningful name (for instance Snippets.vssettings). Commit to source control and push to the cloud. By the way, this also has the advantage of applying source control to the snippets file (which is an XML file), so you get history for free on that file! Reimporting the snippets If VS loses its settings and you need to reimport the snippets, this can be done super easily and very fast. Make sure that the Toolbox is empty. When you import snippets, they are merged with existing ones, they do not replace the content of the Toolbox. Unless merging is really what you want, make sure that your Toolbox is clean before you import, it is really easier. Select the menu Tools, Import and Export Settings. Select Import selected environment settings and press Next. Select No, just import new settings and press Next. Press Browse and select the Snippets.vssettings file. Press Finish. Et voila, all your snippets appear again in the Toolbox. Whew, the worst was averted and you can start your demo without sweating! (I had to do that once literally 5 minutes before the start of a demo, while my laptop was already hooked to the projector, and it went just fine). What about special tools? When using special tools (for example beta versions of tools you have an early access to), or a special configuration of your laptop, things can get tricky because you cannot really be sure that you will get a laptop with the same tools and the same configuration at the conference. To solve that, I use the following precautions: I make my demos from a Virtual Hard Disk. The great John Papa made a very easy-to-follow web page where he explains how to create a VHD and install Win7 to it. This gives you the full power of your laptop (as fast as booting from the metal). For me, I have a basic configuration that I saved on a USB harddrive (Win7 plus drivers, basic settings for desktop, folder options, taskbar etc) and Visual Studio 2010 SP1 on it. When preparing, I start by copying this "basis VHD" to my laptop. I install additional tools and configurations. I save the VHD back to the USB harddrive in a different folder. This would allow me to reinstall my demo environment quite fast, for example in case of harddrive failure. Replace the harddrive, copy the VHD to it, configure the BCD and you can start. Unfortunately this only works if the laptop itself still works. In the worst case of total failure, my security is to back all the installers up: The installers I use are synched on all my laptops and backed up to BackBlaze. If the worst happens and my laptop is absolutely broken, I can download the installer from BackBlaze and install on another laptop. This of course takes some time, and if that happens 5 minutes before a presentation, well… I don't have an answer to that, except of course crossing my fingers. Still, all that gives me additional security. Conclusion Remember folks, talking to an audience, large or small, will make you nervous. Just ask Scott Hanselman :) The goal here is to create the best possible conditions for you, and to create an environment where everything is saved and easy to restore, where everything is well known and provides you with additional confidence. The cooler you feel before the presentation (and during ;)), the better your presentation will be. Here too, the goal is to provide the best user experience you can have, which in turn will make it more enjoyable for your audience! Happy presenting :) Laurent   Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

  Read the article

• iphone - UIViewController header view errors

  - by Fiona

  Hi there, So to give a little background: I've an app that has a UITableViewController- (ContactDetailViewController) In this view at the top, I require a few labels and buttons, followed by a group style tableview. So I've created a nib file containing these elements. (ContactHeaderView.xib) Then in the viewDidLoad of ContactDetailViewController I've loaded this nib as the headerView. See implementation file below: #import "ContactDetailViewController.h" #import "DisplayInfoViewController.h" #import "ActionViewController.h" @implementation ContactDetailViewController @synthesize name; @synthesize date; @synthesize nextAction; @synthesize nameLabel; @synthesize usernameLabel; @synthesize nextActionTextField; @synthesize dateLabel; @synthesize contactInfoButton; @synthesize backgroundInfoButton; @synthesize actionDoneButton; - (void)viewDidLoad { [super viewDidLoad]; } - (void)didReceiveMemoryWarning { // Releases the view if it doesn't have a superview. [super didReceiveMemoryWarning]; // Release any cached data, images, etc that aren't in use. } - (void)viewDidUnload { // Release any retained subviews of the main view. // e.g. self.myOutlet = nil; } #pragma mark Table view methods - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView { return 1; } // Customize the number of rows in the table view. - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { return 3; } - (UIView *) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section { if (section == 0){ UIViewController *chv = [[[UIViewController alloc] initWithNibName:@"ContactHeaderView" bundle:nil] autorelease]; // self.nameLabel.text = self.name; return chv.view; }else{ return nil; } } - (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section{ return 300.0; } // Customize the appearance of table view cells. - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { static NSString *CellIdentifier = @"Cell"; UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; if (cell == nil) { cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; } // Set up the cell... return cell; } - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { // Navigation logic may go here. Create and push another view controller. // AnotherViewController *anotherViewController = [[AnotherViewController alloc] initWithNibName:@"AnotherView" bundle:nil]; // [self.navigationController pushViewController:anotherViewController]; // [anotherViewController release]; } /* // Override to support conditional editing of the table view. - (BOOL)tableView:(UITableView *)tableView canEditRowAtIndexPath:(NSIndexPath *)indexPath { // Return NO if you do not want the specified item to be editable. return YES; } */ - (void)dealloc { [name release]; [date release]; [nextAction release]; [nameLabel release]; [usernameLabel release]; [nextActionTextField release]; [dateLabel release]; [contactInfoButton release]; [backgroundInfoButton release]; [actionDoneButton release]; [super dealloc]; } -(IBAction)displayContactInfo:(id)sender{ DisplayInfoViewController *divc = [[DisplayInfoViewController alloc] init]; divc.textView = self.nextAction; divc.title = @"Contact Info"; [self.navigationController pushViewController:divc animated:YES]; [divc release]; } -(IBAction)displayBackgroundInfo:(id)sender{ DisplayInfoViewController *divc = [[DisplayInfoViewController alloc] init]; divc.textView = self.nextAction; divc.title = @"Background Info"; [self.navigationController pushViewController:divc animated:YES]; [divc release]; } -(IBAction)actionDone:(id)sender{ ActionViewController *avc = [[ActionViewController alloc] init]; avc.title = @"Action"; avc.nextAction = self.nextAction; [self.navigationController pushViewController:avc animated:YES]; [avc release]; } @end Here's the Header File: #import <UIKit/UIKit.h> @interface ContactDetailViewController : UITableViewController { NSString *name; NSString *date; NSString *nextAction; IBOutlet UILabel *nameLabel; IBOutlet UILabel *usernameLabel; IBOutlet UITextField *nextActionTextField; IBOutlet UILabel *dateLabel; IBOutlet UIButton *contactInfoButton; IBOutlet UIButton *backgroundInfoButton; IBOutlet UIButton *actionDoneButton; } @property (nonatomic, retain) NSString *name; @property (nonatomic, retain) NSString *date; @property (nonatomic, retain) NSString *nextAction; @property (nonatomic, retain) IBOutlet UILabel *nameLabel; @property (nonatomic, retain) IBOutlet UILabel *usernameLabel; @property (nonatomic, retain) IBOutlet UITextField *nextActionTextField; @property (nonatomic, retain) IBOutlet UILabel *dateLabel; @property (nonatomic, retain) IBOutlet UIButton *contactInfoButton; @property (nonatomic, retain) IBOutlet UIButton *backgroundInfoButton; @property (nonatomic, retain) IBOutlet UIButton *actionDoneButton; -(IBAction)displayContactInfo: (id)sender; -(IBAction)displayBackgroundInfo: (id)sender; -(IBAction)actionDone: (id)sender; @end However when I run it, I get the following error message: * Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key nameLabel.' In IB I've hooked up the labels/buttons/textbox to the File's Owner (set the File's Owner Class to: ContactDetailViewController) Anyone any idea what I'm doing wrong? Regards, Fiona

  Read the article

• Tips for XNA WP7 Developers

  - by Michael B. McLaughlin

  There are several things any XNA developer should know/consider when coming to the Windows Phone 7 platform. This post assumes you are familiar with the XNA Framework and with the changes between XNA 3.1 and XNA 4.0. It’s not exhaustive; it’s simply a list of things I’ve gathered over time. I may come back and add to it over time, and I’m happy to add anything anyone else has experienced or learned as well. Display · The screen is either 800x480 or 480x800. · But you aren’t required to use only those resolutions. · The hardware scaler on the phone will scale up from 240x240. · One dimension will be capped at 800 and the other at 480; which depends on your code, but you cannot have, e.g., an 800x600 back buffer – that will be created as 800x480. · The hardware scaler will not normally change aspect ratio, though, so no unintended stretching. · Any dimension (width, height, or both) below 240 will be adjusted to 240 (without any aspect ratio adjustment such that, e.g. 200x240 will be treated as 240x240). · Dimensions below 240 will be honored in terms of calculating whether to use portrait or landscape. · If dimensions are exactly equal or if height is greater than width then game will be in portrait. · If width is greater than height, the game will be in landscape. · Landscape games will automatically flip if the user turns the phone 180°; no code required. · Default landscape is top = left. In other words a user holding a phone who starts a landscape game will see the first image presented so that the “top” of the screen is along the right edge of his/her phone, such that the natural behavior would be to turn the phone 90° so that the top of the phone will be held in the user’s left hand and the bottom would be held in the user’s right hand. · The status bar (where the clock, battery power, etc., are found) is hidden when the Game-derived class sets GraphicsDeviceManager.IsFullScreen = true. It is shown when IsFullScreen = false. The default value is false (i.e. the status bar is shown). · You should have a good reason for hiding the status bar. Users find it helpful to know what time it is, how much charge their battery has left, and whether or not their phone is in service range. This is especially true for casual games that you expect someone to play for a few minutes at a time, e.g. while waiting for some event to start, for a phone call to come in, or for a train, bus, or subway to arrive. · In portrait mode, the status bar occupies 32 pixels of space. This means that a game with a back buffer of 480x800 will be scaled down to occupy approximately 461x768 screen pixels. Setting the back buffer to 480x768 (or some resolution with the same 0.625 aspect ratio) will avoid this scaling. · In landscape mode, the status bar occupies 72 pixels of space. This means that a game with a back buffer of 800x480 will be scaled down to occupy approximately 728x437 screen pixels. Setting the back buffer to 728x480 (or some resolution with the same 1.51666667 aspect ratio) will avoid this scaling. Input · Touch input is scaled with screen size. · So if your back buffer is 600x360, a tap in the bottom right corner will come in as (599,359). You don’t need to do anything special to get this automatic scaling of touch behavior. · If you do not use full area of the screen, any touch input outside the area you use will still register as a touch input. For example, if you set a portrait resolution of 240x240, it would be scaled up to occupy a 480x480 area, centered in the screen. If you touch anywhere above this area, you will get a touch input of (X,0) where X is a number from 0 to 239 (in accordance with your 240 pixel wide back buffer). Any touch below this area will give a touch input of (X,239). · If you keep the status bar visible, touches within its area will not be passed to your game. · In general, a screen measurement is the diagonal. So a 3.5” screen is 3.5” long from the bottom right corner to the top left corner. With an aspect ratio of 0.6 (480/800 = 0.6), this means that a phone with a 3.5” screen is only approximately 1.8” wide by 3” tall. So there are approximately 267 pixels in an inch on a 3.5” screen. · Again, this time in metric! 3.5 inches is approximately 8.89 cm. So an 8.89 cm screen is 8.89 cm long from the bottom right corner to the top left corner. With an aspect ratio of 0.6, this means that a phone with an 8.89 cm screen is only approximately 4.57 cm wide by 7.62 cm tall. So there are approximately 105 pixels in a centimeter on an 8.89 cm screen. · Think about the size of your finger tip. If you do not have large hands, think about the size of the fingertip of someone with large hands. Consider that when you are sizing your touch input. Especially consider that when you are spacing two touch targets near one another. You need to judge it for yourself, but items that are next to each other and are each 100x100 should be fine when it comes to selecting items individually. Smaller targets than that are ok provided that you leave space between them. · You want your users to have a pleasant experience. Making touch controls too small or too close to one another will make them nervous about whether they will touch the right target. Take this into account when you plan out your game initially. If possible, do some quick size mockups on an actual phone using colored rectangles that you position and size where you plan to have your game controls. Adjust as necessary. · People do not have transparent hands! Nor are their hands the size of a mouse pointer icon. Consider leaving a dedicated space for input rather than forcing the user to cover up to one-third of the screen with a finger just to play the game. · Another benefit of designing your controls to use a dedicated area is that you’re less likely to have players moving their finger(s) so frantically that they accidentally hit the back button, start button, or search button (many phones have one or more of these on the screen itself – it’s easy to hit one by accident and really annoying if you hit, e.g., the search button and then quickly tap back only to find out that the game didn’t save your progress such that you just wasted all the time you spent playing). · People do not like doing somersaults in order to move something forward with accelerometer-based controls. Test your accelerometer-based controls extensively and get a lot of feedback. Very well-known games from noted publishers have created really bad accelerometer controls and been virtually unplayable as a result. Also be wary of exceptions and other possible failures that the documentation warns about. · When done properly, the accelerometer can add a nice touch to your game (see, e.g. ilomilo where the accelerometer was used to move the background; it added a nice touch without frustrating the user; I also think CarniVale does direct accelerometer controls very well). However, if done poorly, it will make your game an abomination unto the Marketplace. Days, weeks, perhaps even months of development time that you will never get back. I won’t name names; you can search the marketplace for games with terrible reviews and you’ll find them. Graphics · The maximum frame rate is 30 frames per second. This was set as a compromise between battery life and quality. · At least one model of phone is known to have a screen refresh rate that is between 59 and 60 hertz. Because of this, using a fixed time step with a target frame rate of 30 will cause a slight internal delay to build up as the framework is forced to wait slightly for the next refresh. Eventually the delay will get to the point where a draw is skipped in order to recover from the delay. (See Nick's comment below for clarification.) · To deal with that delay, you can either stay with a fixed time step and set the frame rate slightly lower or else you can go to a variable time step and make sure to adjust all of your update data (e.g. player movement distance) to take into account the elapsed time from the last update. A variable time step makes your update logic slightly more complicated but will avoid frame skips entirely. · Currently there are no custom shaders. This might change in the future (there is no hardware limitation preventing it; it simply wasn’t a feature that could be implemented in the time available before launch). · There are five built-in shaders. You can create a lot of nice effects with the built-in shaders. · There is more power on the CPU than there is on the GPU so things you might typically off-load to the GPU will instead make sense to do on the CPU side. · This is a phone. It is not a PC. It is not an Xbox 360. The emulator runs on a PC and uses the full power of your PC. It is very good for testing your code for bugs and doing early prototyping and layout. You should not use it to measure performance. Use actual phone hardware instead. · There are many phone models, each of which has slightly different performance levels for I/O, screen blitting, CPU performance, etc. Do not take your game right to the performance limit on your phone since for some other phones you might be crossing their limits and leaving players with a bad experience. Leave a cushion to account for hardware differences. · Smaller screened phones will have slightly more dots per inch (dpi). Larger screened phones will have slightly less. Either way, the dpi will be much higher than the typical 96 found on most computer screens. Make sure that whoever is doing art for your game takes this into account. · Screens are only required to have 16 bit color (65,536 colors). This is common among smart phones. Using gradients on a 16 bit display can produce an ugly artifact known as banding. Banding is when, rather than a smooth transition from one color to another, you instead see distinct lines. Be careful to avoid this when possible. Banding can be avoided through careful art creation. Its effects can be minimized and even unnoticeable when the texture in question is always moving. You should be careful not to rely on “looks good on my phone” since some phones do have 32-bit displays and thus you’ll find yourself wondering why you’re getting bad reviews that complain about the graphics. Avoid gradients; if you can’t, make sure they are 16-bit safe. Audio · Never rely on sounds as your sole signal to the player that something is happening in the game. They might have the sound off. They might be playing somewhere loud. Etc. · You have to provide controls to disable sound & music. These should be separate. · On at least one model of phone, the volume control API currently has no effect. Players can adjust sound with their hardware volume buttons, but in game selectors simply won’t work. As such, it may not be worth the effort of providing anything beyond on/off switches for sound and music. · MediaPlayer.GameHasControl will return true when a game is hooked up to a PC running Zune. When Zune is running, any attempts to do anything (beyond check GameHasControl) with MediaPlayer will cause an exception to be thrown. If this exception is thrown, catch it and disable music. Exceptions take time to propagate; you don’t want one popping up in every single run of your game’s Update method. · Remember that players can already be listening to music or using the FM radio. In this case GameHasControl will be false and you should handle this appropriately. You can, alternately, ask the player for permission to stop their current music and play your music instead, but the (current) requirement that you restore their music when done is very hard (if not impossible) to deal with. · You can still play sound effects even when the game doesn’t have control of the music, but don’t think this is a backdoor to playing music. Your game will fail certification if your “sound effect” seems to be more like music in scope and length.

  Read the article

• Top things web developers should know about the Visual Studio 2013 release

  - by Jon Galloway

  ASP.NET and Web Tools for Visual Studio 2013 Release NotesASP.NET and Web Tools for Visual Studio 2013 Release NotesSummary for lazy readers: Visual Studio 2013 is now available for download on the Visual Studio site and on MSDN subscriber downloads) Visual Studio 2013 installs side by side with Visual Studio 2012 and supports round-tripping between Visual Studio versions, so you can try it out without committing to a switch Visual Studio 2013 ships with the new version of ASP.NET, which includes ASP.NET MVC 5, ASP.NET Web API 2, Razor 3, Entity Framework 6 and SignalR 2.0 The new releases ASP.NET focuses on One ASP.NET, so core features and web tools work the same across the platform (e.g. adding ASP.NET MVC controllers to a Web Forms application) New core features include new templates based on Bootstrap, a new scaffolding system, and a new identity system Visual Studio 2013 is an incredible editor for web files, including HTML, CSS, JavaScript, Markdown, LESS, Coffeescript, Handlebars, Angular, Ember, Knockdown, etc. Top links: Visual Studio 2013 content on the ASP.NET site are in the standard new releases area: http://www.asp.net/vnext ASP.NET and Web Tools for Visual Studio 2013 Release Notes Short intro videos on the new Visual Studio web editor features from Scott Hanselman and Mads Kristensen Announcing release of ASP.NET and Web Tools for Visual Studio 2013 post on the official .NET Web Development and Tools Blog Scott Guthrie's post: Announcing the Release of Visual Studio 2013 and Great Improvements to ASP.NET and Entity Framework Okay, for those of you who are still with me, let's dig in a bit. Quick web dev notes on downloading and installing Visual Studio 2013 I found Visual Studio 2013 to be a pretty fast install. According to Brian Harry's release post, installing over pre-release versions of Visual Studio is supported.  I've installed the release version over pre-release versions, and it worked fine. If you're only going to be doing web development, you can speed up the install if you just select Web Developer tools. Of course, as a good Microsoft employee, I'll mention that you might also want to install some of those other features, like the Store apps for Windows 8 and the Windows Phone 8.0 SDK, but they do download and install a lot of other stuff (e.g. the Windows Phone SDK sets up Hyper-V and downloads several GB's of VM's). So if you're planning just to do web development for now, you can pick just the Web Developer Tools and install the other stuff later. If you've got a fast internet connection, I recommend using the web installer instead of downloading the ISO. The ISO includes all the features, whereas the web installer just downloads what you're installing. Visual Studio 2013 development settings and color theme When you start up Visual Studio, it'll prompt you to pick some defaults. These are totally up to you -whatever suits your development style - and you can change them later. As I said, these are completely up to you. I recommend either the Web Development or Web Development (Code Only) settings. The only real difference is that Code Only hides the toolbars, and you can switch between them using Tools / Import and Export Settings / Reset. Web Development settings Web Development (code only) settings Usually I've just gone with Web Development (code only) in the past because I just want to focus on the code, although the Standard toolbar does make it easier to switch default web browsers. More on that later. Color theme Sigh. Okay, everyone's got their favorite colors. I alternate between Light and Dark depending on my mood, and I personally like how the low contrast on the window chrome in those themes puts the emphasis on my code rather than the tabs and toolbars. I know some people got pretty worked up over that, though, and wanted the blue theme back. I personally don't like it - it reminds me of ancient versions of Visual Studio that I don't want to think about anymore. So here's the thing: if you install Visual Studio Ultimate, it defaults to Blue. The other versions default to Light. If you use Blue, I won't criticize you - out loud, that is. You can change themes really easily - either Tools / Options / Environment / General, or the smart way: ctrl+q for quick launch, then type Theme and hit enter. Signing in During the first run, you'll be prompted to sign in. You don't have to - you can click the "Not now, maybe later" link at the bottom of that dialog. I recommend signing in, though. It's not hooked in with licensing or tracking the kind of code you write to sell you components. It is doing good things, like  syncing your Visual Studio settings between computers. More about that here. So, you don't have to, but I sure do. Overview of shiny new things in ASP.NET land There are a lot of good new things in ASP.NET. I'll list some of my favorite here, but you can read more on the ASP.NET site. One ASP.NET You've heard us talk about this for a while. The idea is that options are good, but choice can be a burden. When you start a new ASP.NET project, why should you have to make a tough decision - with long-term consequences - about how your application will work? If you want to use ASP.NET Web Forms, but have the option of adding in ASP.NET MVC later, why should that be hard? It's all ASP.NET, right? Ideally, you'd just decide that you want to use ASP.NET to build sites and services, and you could use the appropriate tools (the green blocks below) as you needed them. So, here it is. When you create a new ASP.NET application, you just create an ASP.NET application. Next, you can pick from some templates to get you started... but these are different. They're not "painful decision" templates, they're just some starting pieces. And, most importantly, you can mix and match. I can pick a "mostly" Web Forms template, but include MVC and Web API folders and core references. If you've tried to mix and match in the past, you're probably aware that it was possible, but not pleasant. ASP.NET MVC project files contained special project type GUIDs, so you'd only get controller scaffolding support in a Web Forms project if you manually edited the csproj file. Features in one stack didn't work in others. Project templates were painful choices. That's no longer the case. Hooray! I just did a demo in a presentation last week where I created a new Web Forms + MVC + Web API site, built a model, scaffolded MVC and Web API controllers with EF Code First, add data in the MVC view, viewed it in Web API, then added a GridView to the Web Forms Default.aspx page and bound it to the Model. In about 5 minutes. Sure, it's a simple example, but it's great to be able to share code and features across the whole ASP.NET family. Authentication In the past, authentication was built into the templates. So, for instance, there was an ASP.NET MVC 4 Intranet Project template which created a new ASP.NET MVC 4 application that was preconfigured for Windows Authentication. All of that authentication stuff was built into each template, so they varied between the stacks, and you couldn't reuse them. You didn't see a lot of changes to the authentication options, since they required big changes to a bunch of project templates. Now, the new project dialog includes a common authentication experience. When you hit the Change Authentication button, you get some common options that work the same way regardless of the template or reference settings you've made. These options work on all ASP.NET frameworks, and all hosting environments (IIS, IIS Express, or OWIN for self-host) The default is Individual User Accounts: This is the standard "create a local account, using username / password or OAuth" thing; however, it's all built on the new Identity system. More on that in a second. The one setting that has some configuration to it is Organizational Accounts, which lets you configure authentication using Active Directory, Windows Azure Active Directory, or Office 365. Identity There's a new identity system. We've taken the best parts of the previous ASP.NET Membership and Simple Identity systems, rolled in a lot of feedback and made big enhancements to support important developer concerns like unit testing and extensiblity. I've written long posts about ASP.NET identity, and I'll do it again. Soon. This is not that post. The short version is that I think we've finally got just the right Identity system. Some of my favorite features: There are simple, sensible defaults that work well - you can File / New / Run / Register / Login, and everything works. It supports standard username / password as well as external authentication (OAuth, etc.). It's easy to customize without having to re-implement an entire provider. It's built using pluggable pieces, rather than one large monolithic system. It's built using interfaces like IUser and IRole that allow for unit testing, dependency injection, etc. You can easily add user profile data (e.g. URL, twitter handle, birthday). You just add properties to your ApplicationUser model and they'll automatically be persisted. Complete control over how the identity data is persisted. By default, everything works with Entity Framework Code First, but it's built to support changes from small (modify the schema) to big (use another ORM, store your data in a document database or in the cloud or in XML or in the EXIF data of your desktop background or whatever). It's configured via OWIN. More on OWIN and Katana later, but the fact that it's built using OWIN means it's portable. You can find out more in the Authentication and Identity section of the ASP.NET site (and lots more content will be going up there soon). New Bootstrap based project templates The new project templates are built using Bootstrap 3. Bootstrap (formerly Twitter Bootstrap) is a front-end framework that brings a lot of nice benefits: It's responsive, so your projects will automatically scale to device width using CSS media queries. For example, menus are full size on a desktop browser, but on narrower screens you automatically get a mobile-friendly menu. The built-in Bootstrap styles make your standard page elements (headers, footers, buttons, form inputs, tables etc.) look nice and modern. Bootstrap is themeable, so you can reskin your whole site by dropping in a new Bootstrap theme. Since Bootstrap is pretty popular across the web development community, this gives you a large and rapidly growing variety of templates (free and paid) to choose from. Bootstrap also includes a lot of very useful things: components (like progress bars and badges), useful glyphicons, and some jQuery plugins for tooltips, dropdowns, carousels, etc.). Here's a look at how the responsive part works. When the page is full screen, the menu and header are optimized for a wide screen display: When I shrink the page down (this is all based on page width, not useragent sniffing) the menu turns into a nice mobile-friendly dropdown: For a quick example, I grabbed a new free theme off bootswatch.com. For simple themes, you just need to download the boostrap.css file and replace the /content/bootstrap.css file in your project. Now when I refresh the page, I've got a new theme: Scaffolding The big change in scaffolding is that it's one system that works across ASP.NET. You can create a new Empty Web project or Web Forms project and you'll get the Scaffold context menus. For release, we've got MVC 5 and Web API 2 controllers. We had a preview of Web Forms scaffolding in the preview releases, but they weren't fully baked for RTM. Look for them in a future update, expected pretty soon. This scaffolding system wasn't just changed to work across the ASP.NET frameworks, it's also built to enable future extensibility. That's not in this release, but should also hopefully be out soon. Project Readme page This is a small thing, but I really like it. When you create a new project, you get a Project_Readme.html page that's added to the root of your project and opens in the Visual Studio built-in browser. I love it. A long time ago, when you created a new project we just dumped it on you and left you scratching your head about what to do next. Not ideal. Then we started adding a bunch of Getting Started information to the new project templates. That told you what to do next, but you had to delete all of that stuff out of your website. It doesn't belong there. Not ideal. This is a simple HTML file that's not integrated into your project code at all. You can delete it if you want. But, it shows a lot of helpful links that are current for the project you just created. In the future, if we add new wacky project types, they can create readme docs with specific information on how to do appropriately wacky things. Side note: I really like that they used the internal browser in Visual Studio to show this content rather than popping open an HTML page in the default browser. I hate that. It's annoying. If you're doing that, I hope you'll stop. What if some unnamed person has 40 or 90 tabs saved in their browser session? When you pop open your "Thanks for installing my Visual Studio extension!" page, all eleventy billion tabs start up and I wish I'd never installed your thing. Be like these guys and pop stuff Visual Studio specific HTML docs in the Visual Studio browser. ASP.NET MVC 5 The biggest change with ASP.NET MVC 5 is that it's no longer a separate project type. It integrates well with the rest of ASP.NET. In addition to that and the other common features we've already looked at (Bootstrap templates, Identity, authentication), here's what's new for ASP.NET MVC. Attribute routing ASP.NET MVC now supports attribute routing, thanks to a contribution by Tim McCall, the author of http://attributerouting.net. With attribute routing you can specify your routes by annotating your actions and controllers. This supports some pretty complex, customized routing scenarios, and it allows you to keep your route information right with your controller actions if you'd like. Here's a controller that includes an action whose method name is Hiding, but I've used AttributeRouting to configure it to /spaghetti/with-nesting/where-is-waldo public class SampleController : Controller { [Route("spaghetti/with-nesting/where-is-waldo")] public string Hiding() { return "You found me!"; } } I enable that in my RouteConfig.cs, and I can use that in conjunction with my other MVC routes like this: public class RouteConfig { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapMvcAttributeRoutes(); routes.MapRoute( name: "Default", url: "{controller}/{action}/{id}", defaults: new { controller = "Home", action = "Index", id = UrlParameter.Optional } ); } } You can read more about Attribute Routing in ASP.NET MVC 5 here. Filter enhancements There are two new additions to filters: Authentication Filters and Filter Overrides. Authentication filters are a new kind of filter in ASP.NET MVC that run prior to authorization filters in the ASP.NET MVC pipeline and allow you to specify authentication logic per-action, per-controller, or globally for all controllers. Authentication filters process credentials in the request and provide a corresponding principal. Authentication filters can also add authentication challenges in response to unauthorized requests. Override filters let you change which filters apply to a given action method or controller. Override filters specify a set of filter types that should not be run for a given scope (action or controller). This allows you to configure filters that apply globally but then exclude certain global filters from applying to specific actions or controllers. ASP.NET Web API 2 ASP.NET Web API 2 includes a lot of new features. Attribute Routing ASP.NET Web API supports the same attribute routing system that's in ASP.NET MVC 5. You can read more about the Attribute Routing features in Web API in this article. OAuth 2.0 ASP.NET Web API picks up OAuth 2.0 support, using security middleware running on OWIN (discussed below). This is great for features like authenticated Single Page Applications. OData Improvements ASP.NET Web API now has full OData support. That required adding in some of the most powerful operators: $select, $expand, $batch and $value. You can read more about OData operator support in this article by Mike Wasson. Lots more There's a huge list of other features, including CORS (cross-origin request sharing), IHttpActionResult, IHttpRequestContext, and more. I think the best overview is in the release notes. OWIN and Katana I've written about OWIN and Katana recently. I'm a big fan. OWIN is the Open Web Interfaces for .NET. It's a spec, like HTML or HTTP, so you can't install OWIN. The benefit of OWIN is that it's a community specification, so anyone who implements it can plug into the ASP.NET stack, either as middleware or as a host. Katana is the Microsoft implementation of OWIN. It leverages OWIN to wire up things like authentication, handlers, modules, IIS hosting, etc., so ASP.NET can host OWIN components and Katana components can run in someone else's OWIN implementation. Howard Dierking just wrote a cool article in MSDN magazine describing Katana in depth: Getting Started with the Katana Project. He had an interesting example showing an OWIN based pipeline which leveraged SignalR, ASP.NET Web API and NancyFx components in the same stack. If this kind of thing makes sense to you, that's great. If it doesn't, don't worry, but keep an eye on it. You're going to see some cool things happen as a result of ASP.NET becoming more and more pluggable. Visual Studio Web Tools Okay, this stuff's just crazy. Visual Studio has been adding some nice web dev features over the past few years, but they've really cranked it up for this release. Visual Studio is by far my favorite code editor for all web files: CSS, HTML, JavaScript, and lots of popular libraries. Stop thinking of Visual Studio as a big editor that you only use to write back-end code. Stop editing HTML and CSS in Notepad (or Sublime, Notepad++, etc.). Visual Studio starts up in under 2 seconds on a modern computer with an SSD. Misspelling HTML attributes or your CSS classes or jQuery or Angular syntax is stupid. It doesn't make you a better developer, it makes you a silly person who wastes time. Browser Link Browser Link is a real-time, two-way connection between Visual Studio and all connected browsers. It's only attached when you're running locally, in debug, but it applies to any and all connected browser, including emulators. You may have seen demos that showed the browsers refreshing based on changes in the editor, and I'll agree that's pretty cool. But it's really just the start. It's a two-way connection, and it's built for extensiblity. That means you can write extensions that push information from your running application (in IE, Chrome, a mobile emulator, etc.) back to Visual Studio. Mads and team have showed off some demonstrations where they enabled edit mode in the browser which updated the source HTML back on the browser. It's also possible to look at how the rendered HTML performs, check for compatibility issues, watch for unused CSS classes, the sky's the limit. New HTML editor The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Here's a 3 minute tour from Mads Kristensen. The previous HTML editor had a lot of old code that didn't allow for improvements. The team rewrote the HTML editor to take advantage of the new(ish) extensibility features in Visual Studio, which then allowed them to add in all kinds of features - things like CSS Class and ID IntelliSense (so you type style="" and get a list of classes and ID's for your project), smart indent based on how your document is formatted, JavaScript reference auto-sync, etc. Lots more Visual Studio web dev features That's just a sampling - there's a ton of great features for JavaScript editing, CSS editing, publishing, and Page Inspector (which shows real-time rendering of your page inside Visual Studio). Here are some more short videos showing those features. Lots, lots more Okay, that's just a summary, and it's still quite a bit. Head on over to http://asp.net/vnext for more information, and download Visual Studio 2013 now to get started!

  Read the article

• Custom ASP.NET Routing to an HttpHandler

  - by Rick Strahl

  As of version 4.0 ASP.NET natively supports routing via the now built-in System.Web.Routing namespace. Routing features are automatically integrated into the HtttpRuntime via a few custom interfaces. New Web Forms Routing Support In ASP.NET 4.0 there are a host of improvements including routing support baked into Web Forms via a RouteData property available on the Page class and RouteCollection.MapPageRoute() route handler that makes it easy to route to Web forms. To map ASP.NET Page routes is as simple as setting up the routes with MapPageRoute:protected void Application_Start(object sender, EventArgs e) { RegisterRoutes(RouteTable.Routes); } void RegisterRoutes(RouteCollection routes) { routes.MapPageRoute("StockQuote", "StockQuote/{symbol}", "StockQuote.aspx"); routes.MapPageRoute("StockQuotes", "StockQuotes/{symbolList}", "StockQuotes.aspx"); } and then accessing the route data in the page you can then use the new Page class RouteData property to retrieve the dynamic route data information:public partial class StockQuote1 : System.Web.UI.Page { protected StockQuote Quote = null; protected void Page_Load(object sender, EventArgs e) { string symbol = RouteData.Values["symbol"] as string; StockServer server = new StockServer(); Quote = server.GetStockQuote(symbol); // display stock data in Page View } } Simple, quick and doesn’t require much explanation. If you’re using WebForms most of your routing needs should be served just fine by this simple mechanism. Kudos to the ASP.NET team for putting this in the box and making it easy! How Routing Works To handle Routing in ASP.NET involves these steps: Registering Routes Creating a custom RouteHandler to retrieve an HttpHandler Attaching RouteData to your HttpHandler Picking up Route Information in your Request code Registering routes makes ASP.NET aware of the Routes you want to handle via the static RouteTable.Routes collection. You basically add routes to this collection to let ASP.NET know which URL patterns it should watch for. You typically hook up routes off a RegisterRoutes method that fires in Application_Start as I did in the example above to ensure routes are added only once when the application first starts up. When you create a route, you pass in a RouteHandler instance which ASP.NET caches and reuses as routes are matched. Once registered ASP.NET monitors the routes and if a match is found just prior to the HttpHandler instantiation, ASP.NET uses the RouteHandler registered for the route and calls GetHandler() on it to retrieve an HttpHandler instance. The RouteHandler.GetHandler() method is responsible for creating an instance of an HttpHandler that is to handle the request and – if necessary – to assign any additional custom data to the handler. At minimum you probably want to pass the RouteData to the handler so the handler can identify the request based on the route data available. To do this you typically add  a RouteData property to your handler and then assign the property from the RouteHandlers request context. This is essentially how Page.RouteData comes into being and this approach should work well for any custom handler implementation that requires RouteData. It’s a shame that ASP.NET doesn’t have a top level intrinsic object that’s accessible off the HttpContext object to provide route data more generically, but since RouteData is directly tied to HttpHandlers and not all handlers support it it might cause some confusion of when it’s actually available. Bottom line is that if you want to hold on to RouteData you have to assign it to a custom property of the handler or else pass it to the handler via Context.Items[] object that can be retrieved on an as needed basis. It’s important to understand that routing is hooked up via RouteHandlers that are responsible for loading HttpHandler instances. RouteHandlers are invoked for every request that matches a route and through this RouteHandler instance the Handler gains access to the current RouteData. Because of this logic it’s important to understand that Routing is really tied to HttpHandlers and not available prior to handler instantiation, which is pretty late in the HttpRuntime’s request pipeline. IOW, Routing works with Handlers but not with earlier in the pipeline within Modules. Specifically ASP.NET calls RouteHandler.GetHandler() from the PostResolveRequestCache HttpRuntime pipeline event. Here’s the call stack at the beginning of the GetHandler() call: which fires just before handler resolution. Non-Page Routing – You need to build custom RouteHandlers If you need to route to a custom Http Handler or other non-Page (and non-MVC) endpoint in the HttpRuntime, there is no generic mapping support available. You need to create a custom RouteHandler that can manage creating an instance of an HttpHandler that is fired in response to a routed request. Depending on what you are doing this process can be simple or fairly involved as your code is responsible based on the route data provided which handler to instantiate, and more importantly how to pass the route data on to the Handler. Luckily creating a RouteHandler is easy by implementing the IRouteHandler interface which has only a single GetHttpHandler(RequestContext context) method. In this method you can pick up the requestContext.RouteData, instantiate the HttpHandler of choice, and assign the RouteData to it. Then pass back the handler and you’re done.Here’s a simple example of GetHttpHandler() method that dynamically creates a handler based on a passed in Handler type./// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } Note that this code checks for a specific type of handler and if it matches assigns the RouteData to this handler. This is optional but quite a common scenario if you want to work with RouteData. If the handler you need to instantiate isn’t under your control but you still need to pass RouteData to Handler code, an alternative is to pass the RouteData via the HttpContext.Items collection:IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; requestContext.HttpContext.Items["RouteData"] = requestContext.RouteData; return handler; } The code in the handler implementation can then pick up the RouteData from the context collection as needed:RouteData routeData = HttpContext.Current.Items["RouteData"] as RouteData This isn’t as clean as having an explicit RouteData property, but it does have the advantage that the route data is visible anywhere in the Handler’s code chain. It’s definitely preferable to create a custom property on your handler, but the Context work-around works in a pinch when you don’t’ own the handler code and have dynamic code executing as part of the handler execution. An Example of a Custom RouteHandler: Attribute Based Route Implementation In this post I’m going to discuss a custom routine implementation I built for my CallbackHandler class in the West Wind Web & Ajax Toolkit. CallbackHandler can be very easily used for creating AJAX, REST and POX requests following RPC style method mapping. You can pass parameters via URL query string, POST data or raw data structures, and you can retrieve results as JSON, XML or raw string/binary data. It’s a quick and easy way to build service interfaces with no fuss. As a quick review here’s how CallbackHandler works: You create an Http Handler that derives from CallbackHandler You implement methods that have a [CallbackMethod] Attribute and that’s it. Here’s an example of an CallbackHandler implementation in an ashx.cs based handler:// RestService.ashx.cs public class RestService : CallbackHandler { [CallbackMethod] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } } CallbackHandler makes it super easy to create a method on the server, pass data to it via POST, QueryString or raw JSON/XML data, and then retrieve the results easily back in various formats. This works wonderful and I’ve used these tools in many projects for myself and with clients. But one thing missing has been the ability to create clean URLs. Typical URLs looked like this: http://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuote&symbol=msfthttp://www.west-wind.com/WestwindWebToolkit/samples/Rest/StockService.ashx?Method=GetStockQuotes&symbolList=msft,intc,gld,slw,mwe&format=xml which works and is clear enough, but also clearly very ugly. It would be much nicer if URLs could look like this: http://www.west-wind.com//WestwindWebtoolkit/Samples/StockQuote/msfthttp://www.west-wind.com/WestwindWebtoolkit/Samples/StockQuotes/msft,intc,gld,slw?format=xml (the Virtual Root in this sample is WestWindWebToolkit/Samples and StockQuote/{symbol} is the route)(If you use FireFox try using the JSONView plug-in make it easier to view JSON content) So, taking a clue from the WCF REST tools that use RouteUrls I set out to create a way to specify RouteUrls for each of the endpoints. The change made basically allows changing the above to: [CallbackMethod(RouteUrl="RestService/StockQuote/{symbol}")] public StockQuote GetStockQuote(string symbol) { StockServer server = new StockServer(); return server.GetStockQuote(symbol); } [CallbackMethod(RouteUrl = "RestService/StockQuotes/{symbolList}")] public StockQuote[] GetStockQuotes(string symbolList) { StockServer server = new StockServer(); string[] symbols = symbolList.Split(new char[2] { ',',';' },StringSplitOptions.RemoveEmptyEntries); return server.GetStockQuotes(symbols); } where a RouteUrl is specified as part of the Callback attribute. And with the changes made with RouteUrls I can now get URLs like the second set shown earlier. So how does that work? Let’s find out… How to Create Custom Routes As mentioned earlier Routing is made up of several steps: Creating a custom RouteHandler to create HttpHandler instances Mapping the actual Routes to the RouteHandler Retrieving the RouteData and actually doing something useful with it in the HttpHandler In the CallbackHandler routing example above this works out to something like this: Create a custom RouteHandler that includes a property to track the method to call Set up the routes using Reflection against the class Looking for any RouteUrls in the CallbackMethod attribute Add a RouteData property to the CallbackHandler so we can access the RouteData in the code of the handler Creating a Custom Route Handler To make the above work I created a custom RouteHandler class that includes the actual IRouteHandler implementation as well as a generic and static method to automatically register all routes marked with the [CallbackMethod(RouteUrl="…")] attribute. Here’s the code:/// <summary> /// Route handler that can create instances of CallbackHandler derived /// callback classes. The route handler tracks the method name and /// creates an instance of the service in a predictable manner /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler type</typeparam> public class CallbackHandlerRouteHandler : IRouteHandler { /// <summary> /// Method name that is to be called on this route. /// Set by the automatically generated RegisterRoutes /// invokation. /// </summary> public string MethodName { get; set; } /// <summary> /// The type of the handler we're going to instantiate. /// Needed so we can semi-generically instantiate the /// handler and call the method on it. /// </summary> public Type CallbackHandlerType { get; set; } /// <summary> /// Constructor to pass in the two required components we /// need to create an instance of our handler. /// </summary> /// <param name="methodName"></param> /// <param name="callbackHandlerType"></param> public CallbackHandlerRouteHandler(string methodName, Type callbackHandlerType) { MethodName = methodName; CallbackHandlerType = callbackHandlerType; } /// <summary> /// Retrieves an Http Handler based on the type specified in the constructor /// </summary> /// <param name="requestContext"></param> /// <returns></returns> IHttpHandler IRouteHandler.GetHttpHandler(RequestContext requestContext) { IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; // If we're dealing with a Callback Handler // pass the RouteData for this route to the Handler if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; } /// <summary> /// Generic method to register all routes from a CallbackHandler /// that have RouteUrls defined on the [CallbackMethod] attribute /// </summary> /// <typeparam name="TCallbackHandler">CallbackHandler Type</typeparam> /// <param name="routes"></param> public static void RegisterRoutes<TCallbackHandler>(RouteCollection routes) { // find all methods var methods = typeof(TCallbackHandler).GetMethods(BindingFlags.Instance | BindingFlags.Public); foreach (var method in methods) { var attrs = method.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (attrs.Length < 1) continue; CallbackMethodAttribute attr = attrs[0] as CallbackMethodAttribute; if (string.IsNullOrEmpty(attr.RouteUrl)) continue; // Add the route routes.Add(method.Name, new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler)))); } } } The RouteHandler implements IRouteHandler, and its responsibility via the GetHandler method is to create an HttpHandler based on the route data. When ASP.NET calls GetHandler it passes a requestContext parameter which includes a requestContext.RouteData property. This parameter holds the current request’s route data as well as an instance of the current RouteHandler. If you look at GetHttpHandler() you can see that the code creates an instance of the handler we are interested in and then sets the RouteData property on the handler. This is how you can pass the current request’s RouteData to the handler. The RouteData object also has a  RouteData.RouteHandler property that is also available to the Handler later, which is useful in order to get additional information about the current route. In our case here the RouteHandler includes a MethodName property that identifies the method to execute in the handler since that value no longer comes from the URL so we need to figure out the method name some other way. The method name is mapped explicitly when the RouteHandler is created and here the static method that auto-registers all CallbackMethods with RouteUrls sets the method name when it creates the routes while reflecting over the methods (more on this in a minute). The important point here is that you can attach additional properties to the RouteHandler and you can then later access the RouteHandler and its properties later in the Handler to pick up these custom values. This is a crucial feature in that the RouteHandler serves in passing additional context to the handler so it knows what actions to perform. The automatic route registration is handled by the static RegisterRoutes<TCallbackHandler> method. This method is generic and totally reusable for any CallbackHandler type handler. To register a CallbackHandler and any RouteUrls it has defined you simple use code like this in Application_Start (or other application startup code):protected void Application_Start(object sender, EventArgs e) { // Register Routes for RestService CallbackHandlerRouteHandler.RegisterRoutes<RestService>(RouteTable.Routes); } If you have multiple CallbackHandler style services you can make multiple calls to RegisterRoutes for each of the service types. RegisterRoutes internally uses reflection to run through all the methods of the Handler, looking for CallbackMethod attributes and whether a RouteUrl is specified. If it is a new instance of a CallbackHandlerRouteHandler is created and the name of the method and the type are set. routes.Add(method.Name,           new Route(attr.RouteUrl, new CallbackHandlerRouteHandler(method.Name, typeof(TCallbackHandler) )) ); While the routing with CallbackHandlerRouteHandler is set up automatically for all methods that use the RouteUrl attribute, you can also use code to hook up those routes manually and skip using the attribute. The code for this is straightforward and just requires that you manually map each individual route to each method you want a routed: protected void Application_Start(objectsender, EventArgs e){    RegisterRoutes(RouteTable.Routes);}void RegisterRoutes(RouteCollection routes) { routes.Add("StockQuote Route",new Route("StockQuote/{symbol}",                     new CallbackHandlerRouteHandler("GetStockQuote",typeof(RestService) ) ) );     routes.Add("StockQuotes Route",new Route("StockQuotes/{symbolList}",                     new CallbackHandlerRouteHandler("GetStockQuotes",typeof(RestService) ) ) );}I think it’s clearly easier to have CallbackHandlerRouteHandler.RegisterRoutes() do this automatically for you based on RouteUrl attributes, but some people have a real aversion to attaching logic via attributes. Just realize that the option to manually create your routes is available as well. Using the RouteData in the Handler A RouteHandler’s responsibility is to create an HttpHandler and as mentioned earlier, natively IHttpHandler doesn’t have any support for RouteData. In order to utilize RouteData in your handler code you have to pass the RouteData to the handler. In my CallbackHandlerRouteHandler when it creates the HttpHandler instance it creates the instance and then assigns the custom RouteData property on the handler:IHttpHandler handler = Activator.CreateInstance(CallbackHandlerType) as IHttpHandler; if (handler is CallbackHandler) ((CallbackHandler)handler).RouteData = requestContext.RouteData; return handler; Again this only works if you actually add a RouteData property to your handler explicitly as I did in my CallbackHandler implementation:/// <summary> /// Optionally store RouteData on this handler /// so we can access it internally /// </summary> public RouteData RouteData {get; set; } and the RouteHandler needs to set it when it creates the handler instance. Once you have the route data in your handler you can access Route Keys and Values and also the RouteHandler. Since my RouteHandler has a custom property for the MethodName to retrieve it from within the handler I can do something like this now to retrieve the MethodName (this example is actually not in the handler but target is an instance pass to the processor): // check for Route Data method name if (target is CallbackHandler) { var routeData = ((CallbackHandler)target).RouteData; if (routeData != null) methodToCall = ((CallbackHandlerRouteHandler)routeData.RouteHandler).MethodName; } When I need to access the dynamic values in the route ( symbol in StockQuote/{symbol}) I can retrieve it easily with the Values collection (RouteData.Values["symbol"]). In my CallbackHandler processing logic I’m basically looking for matching parameter names to Route parameters: // look for parameters in the routeif(routeData != null){    string parmString = routeData.Values[parameter.Name] as string;    adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType);} And with that we’ve come full circle. We’ve created a custom RouteHandler() that passes the RouteData to the handler it creates. We’ve registered our routes to use the RouteHandler, and we’ve utilized the route data in our handler. For completeness sake here’s the routine that executes a method call based on the parameters passed in and one of the options is to retrieve the inbound parameters off RouteData (as well as from POST data or QueryString parameters):internal object ExecuteMethod(string method, object target, string[] parameters, CallbackMethodParameterType paramType, ref CallbackMethodAttribute callbackMethodAttribute) { HttpRequest Request = HttpContext.Current.Request; object Result = null; // Stores parsed parameters (from string JSON or QUeryString Values) object[] adjustedParms = null; Type PageType = target.GetType(); MethodInfo MI = PageType.GetMethod(method, BindingFlags.Instance | BindingFlags.Public | BindingFlags.NonPublic); if (MI == null) throw new InvalidOperationException("Invalid Server Method."); object[] methods = MI.GetCustomAttributes(typeof(CallbackMethodAttribute), false); if (methods.Length < 1) throw new InvalidOperationException("Server method is not accessible due to missing CallbackMethod attribute"); if (callbackMethodAttribute != null) callbackMethodAttribute = methods[0] as CallbackMethodAttribute; ParameterInfo[] parms = MI.GetParameters(); JSONSerializer serializer = new JSONSerializer(); RouteData routeData = null; if (target is CallbackHandler) routeData = ((CallbackHandler)target).RouteData; int parmCounter = 0; adjustedParms = new object[parms.Length]; foreach (ParameterInfo parameter in parms) { // Retrieve parameters out of QueryString or POST buffer if (parameters == null) { // look for parameters in the route if (routeData != null) { string parmString = routeData.Values[parameter.Name] as string; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // GET parameter are parsed as plain string values - no JSON encoding else if (HttpContext.Current.Request.HttpMethod == "GET") { // Look up the parameter by name string parmString = Request.QueryString[parameter.Name]; adjustedParms[parmCounter] = ReflectionUtils.StringToTypedValue(parmString, parameter.ParameterType); } // POST parameters are treated as methodParameters that are JSON encoded else if (paramType == CallbackMethodParameterType.Json) //string newVariable = methodParameters.GetValue(parmCounter) as string; adjustedParms[parmCounter] = serializer.Deserialize(Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject( Request.Params["parm" + (parmCounter + 1).ToString()], parameter.ParameterType); } else if (paramType == CallbackMethodParameterType.Json) adjustedParms[parmCounter] = serializer.Deserialize(parameters[parmCounter], parameter.ParameterType); else adjustedParms[parmCounter] = SerializationUtils.DeSerializeObject(parameters[parmCounter], parameter.ParameterType); parmCounter++; } Result = MI.Invoke(target, adjustedParms); return Result; } The code basically uses Reflection to loop through all the parameters available on the method and tries to assign the parameters from RouteData, QueryString or POST variables. The parameters are converted into their appropriate types and then used to eventually make a Reflection based method call. What’s sweet is that the RouteData retrieval is just another option for dealing with the inbound data in this scenario and it adds exactly two lines of code plus the code to retrieve the MethodName I showed previously – a seriously low impact addition that adds a lot of extra value to this endpoint callback processing implementation. Debugging your Routes If you create a lot of routes it’s easy to run into Route conflicts where multiple routes have the same path and overlap with each other. This can be difficult to debug especially if you are using automatically generated routes like the routes created by CallbackHandlerRouteHandler.RegisterRoutes. Luckily there’s a tool that can help you out with this nicely. Phill Haack created a RouteDebugging tool you can download and add to your project. The easiest way to do this is to grab and add this to your project is to use NuGet (Add Library Package from your Project’s Reference Nodes):   which adds a RouteDebug assembly to your project. Once installed you can easily debug your routes with this simple line of code which needs to be installed at application startup:protected void Application_Start(object sender, EventArgs e) { CallbackHandlerRouteHandler.RegisterRoutes<StockService>(RouteTable.Routes); // Debug your routes RouteDebug.RouteDebugger.RewriteRoutesForTesting(RouteTable.Routes); } Any routed URL then displays something like this: The screen shows you your current route data and all the routes that are mapped along with a flag that displays which route was actually matched. This is useful – if you have any overlap of routes you will be able to see which routes are triggered – the first one in the sequence wins. This tool has saved my ass on a few occasions – and with NuGet now it’s easy to add it to your project in a few seconds and then remove it when you’re done. Routing Around Custom routing seems slightly complicated on first blush due to its disconnected components of RouteHandler, route registration and mapping of custom handlers. But once you understand the relationship between a RouteHandler, the RouteData and how to pass it to a handler, utilizing of Routing becomes a lot easier as you can easily pass context from the registration to the RouteHandler and through to the HttpHandler. The most important thing to understand when building custom routing solutions is to figure out how to map URLs in such a way that the handler can figure out all the pieces it needs to process the request. This can be via URL routing parameters and as I did in my example by passing additional context information as part of the RouteHandler instance that provides the proper execution context. In my case this ‘context’ was the method name, but it could be an actual static value like an enum identifying an operation or category in an application. Basically user supplied data comes in through the url and static application internal data can be passed via RouteHandler property values. Routing can make your application URLs easier to read by non-techie types regardless of whether you’re building Service type or REST applications, or full on Web interfaces. Routing in ASP.NET 4.0 makes it possible to create just about any extensionless URLs you can dream up and custom RouteHanmdler References Sample ProjectIncludes the sample CallbackHandler service discussed here along with compiled versionsof the Westwind.Web and Westwind.Utilities assemblies.  (requires .NET 4.0/VS 2010) West Wind Web Toolkit includes full implementation of CallbackHandler and the Routing Handler West Wind Web Toolkit Source CodeContains the full source code to the Westwind.Web and Westwind.Utilities assemblies usedin these samples. Includes the source described in the post.(Latest build in the Subversion Repository) CallbackHandler Source(Relevant code to this article tree in Westwind.Web assembly) JSONView FireFoxPluginA simple FireFox Plugin to easily view JSON data natively in FireFox.For IE you can use a registry hack to display JSON as raw text.© Rick Strahl, West Wind Technologies, 2005-2011Posted in ASP.NET  AJAX  HTTP  

  Read the article

• Using HTML 5 SessionState to save rendered Page Content

  - by Rick Strahl

  HTML 5 SessionState and LocalStorage are very useful and super easy to use to manage client side state. For building rich client side or SPA style applications it's a vital feature to be able to cache user data as well as HTML content in order to swap pages in and out of the browser's DOM. What might not be so obvious is that you can also use the sessionState and localStorage objects even in classic server rendered HTML applications to provide caching features between pages. These APIs have been around for a long time and are supported by most relatively modern browsers and even all the way back to IE8, so you can use them safely in your Web applications. SessionState and LocalStorage are easy The APIs that make up sessionState and localStorage are very simple. Both object feature the same API interface which  is a simple, string based key value store that has getItem, setItem, removeitem, clear and  key methods. The objects are also pseudo array objects and so can be iterated like an array with  a length property and you have array indexers to set and get values with. Basic usage  for storing and retrieval looks like this (using sessionStorage, but the syntax is the same for localStorage - just switch the objects):// set var lastAccess = new Date().getTime(); if (sessionStorage) sessionStorage.setItem("myapp_time", lastAccess.toString()); // retrieve in another page or on a refresh var time = null; if (sessionStorage) time = sessionStorage.getItem("myapp_time"); if (time) time = new Date(time * 1); else time = new Date(); sessionState stores data that is browser session specific and that has a liftetime of the active browser session or window. Shut down the browser or tab and the storage goes away. localStorage uses the same API interface, but the lifetime of the data is permanently stored in the browsers storage area until deleted via code or by clearing out browser cookies (not the cache). Both sessionStorage and localStorage space is limited. The spec is ambiguous about this - supposedly sessionStorage should allow for unlimited size, but it appears that most WebKit browsers support only 2.5mb for either object. This means you have to be careful what you store especially since other applications might be running on the same domain and also use the storage mechanisms. That said 2.5mb worth of character data is quite a bit and would go a long way. The easiest way to get a feel for how sessionState and localStorage work is to look at a simple example. You can go check out the following example online in Plunker: http://plnkr.co/edit/0ICotzkoPjHaWa70GlRZ?p=preview which looks like this: Plunker is an online HTML/JavaScript editor that lets you write and run Javascript code and similar to JsFiddle, but a bit cleaner to work in IMHO (thanks to John Papa for turning me on to it). The sample has two text boxes with counts that update session/local storage every time you click the related button. The counts are 'cached' in Session and Local storage. The point of these examples is that both counters survive full page reloads, and the LocalStorage counter survives a complete browser shutdown and restart. Go ahead and try it out by clicking the Reload button after updating both counters and then shutting down the browser completely and going back to the same URL (with the same browser). What you should see is that reloads leave both counters intact at the counted values, while a browser restart will leave only the local storage counter intact. The code to deal with the SessionStorage (and LocalStorage not shown here) in the example is isolated into a couple of wrapper methods to simplify the code: function getSessionCount() { var count = 0; if (sessionStorage) { var count = sessionStorage.getItem("ss_count"); count = !count ? 0 : count * 1; } $("#txtSession").val(count); return count; } function setSessionCount(count) { if (sessionStorage) sessionStorage.setItem("ss_count", count.toString()); } These two functions essentially load and store a session counter value. The two key methods used here are: sessionStorage.getItem(key); sessionStorage.setItem(key,stringVal); Note that the value given to setItem and return by getItem has to be a string. If you pass another type you get an error. Don't let that limit you though - you can easily enough store JSON data in a variable so it's quite possible to pass complex objects and store them into a single sessionStorage value:var user = { name: "Rick", id="ricks", level=8 } sessionStorage.setItem("app_user",JSON.stringify(user)); to retrieve it:var user = sessionStorage.getItem("app_user"); if (user) user = JSON.parse(user); Simple! If you're using the Chrome Developer Tools (F12) you can also check out the session and local storage state on the Resource tab:   You can also use this tool to refresh or remove entries from storage. What we just looked at is a purely client side implementation where a couple of counters are stored. For rich client centric AJAX applications sessionStorage and localStorage provide a very nice and simple API to store application state while the application is running. But you can also use these storage mechanisms to manage server centric HTML applications when you combine server rendering with some JavaScript to perform client side data caching. You can both store some state information and data on the client (ie. store a JSON object and carry it forth between server rendered HTML requests) or you can use it for good old HTTP based caching where some rendered HTML is saved and then restored later. Let's look at the latter with a real life example. Why do I need Client-side Page Caching for Server Rendered HTML? I don't know about you, but in a lot of my existing server driven applications I have lists that display a fair amount of data. Typically these lists contain links to then drill down into more specific data either for viewing or editing. You can then click on a link and go off to a detail page that provides more concise content. So far so good. But now you're done with the detail page and need to get back to the list, so you click on a 'bread crumbs trail' or an application level 'back to list' button and… …you end up back at the top of the list - the scroll position, the current selection in some cases even filters conditions - all gone with the wind. You've left behind the state of the list and are starting from scratch in your browsing of the list from the top. Not cool! Sound familiar? This a pretty common scenario with server rendered HTML content where it's so common to display lists to drill into, only to lose state in the process of returning back to the original list. Look at just about any traditional forums application, or even StackOverFlow to see what I mean here. Scroll down a bit to look at a post or entry, drill in then use the bread crumbs or tab to go back… In some cases returning to the top of a list is not a big deal. On StackOverFlow that sort of works because content is turning around so quickly you probably want to actually look at the top posts. Not always though - if you're browsing through a list of search topics you're interested in and drill in there's no way back to that position. Essentially anytime you're actively browsing the items in the list, that's when state becomes important and if it's not handled the user experience can be really disrupting. Content Caching If you're building client centric SPA style applications this is a fairly easy to solve problem - you tend to render the list once and then update the page content to overlay the detail content, only hiding the list temporarily until it's used again later. It's relatively easy to accomplish this simply by hiding content on the page and later making it visible again. But if you use server rendered content, hanging on to all the detail like filters, selections and scroll position is not quite as easy. Or is it??? This is where sessionStorage comes in handy. What if we just save the rendered content of a previous page, and then restore it when we return to this page based on a special flag that tells us to use the cached version? Let's see how we can do this. A real World Use Case Recently my local ISP asked me to help out with updating an ancient classifieds application. They had a very busy, local classifieds app that was originally an ASP classic application. The old app was - wait for it: frames based - and even though I lobbied against it, the decision was made to keep the frames based layout to allow rapid browsing of the hundreds of posts that are made on a daily basis. The primary reason they wanted this was precisely for the ability to quickly browse content item by item. While I personally hate working with Frames, I have to admit that the UI actually works well with the frames layout as long as you're running on a large desktop screen. You can check out the frames based desktop site here: http://classifieds.gorge.net/ However when I rebuilt the app I also added a secondary view that doesn't use frames. The main reason for this of course was for mobile displays which work horribly with frames. So there's a somewhat mobile friendly interface to the interface, which ditches the frames and uses some responsive design tweaking for mobile capable operation: http://classifeds.gorge.net/mobile  (or browse the base url with your browser width under 800px)   Here's what the mobile, non-frames view looks like:   As you can see this means that the list of classifieds posts now is a list and there's a separate page for drilling down into the item. And of course… originally we ran into that usability issue I mentioned earlier where the browse, view detail, go back to the list cycle resulted in lost list state. Originally in mobile mode you scrolled through the list, found an item to look at and drilled in to display the item detail. Then you clicked back to the list and BAM - you've lost your place. Because there are so many items added on a daily basis the full list is never fully loaded, but rather there's a "Load Additional Listings"  entry at the button. Not only did we originally lose our place when coming back to the list, but any 'additionally loaded' items are no longer there because the list was now rendering  as if it was the first page hit. The additional listings, and any filters, the selection of an item all were lost. Major Suckage! Using Client SessionStorage to cache Server Rendered Content To work around this problem I decided to cache the rendered page content from the list in SessionStorage. Anytime the list renders or is updated with Load Additional Listings, the page HTML is cached and stored in Session Storage. Any back links from the detail page or the login or write entry forms then point back to the list page with a back=true query string parameter. If the server side sees this parameter it doesn't render the part of the page that is cached. Instead the client side code retrieves the data from the sessionState cache and simply inserts it into the page. It sounds pretty simple, and the overall the process is really easy, but there are a few gotchas that I'll discuss in a minute. But first let's look at the implementation. Let's start with the server side here because that'll give a quick idea of the doc structure. As I mentioned the server renders data from an ASP.NET MVC view. On the list page when returning to the list page from the display page (or a host of other pages) looks like this: https://classifieds.gorge.net/list?back=True The query string value is a flag, that indicates whether the server should render the HTML. Here's what the top level MVC Razor view for the list page looks like:@model MessageListViewModel @{ ViewBag.Title = "Classified Listing"; bool isBack = !string.IsNullOrEmpty(Request.QueryString["back"]); } <form method="post" action="@Url.Action("list")"> <div id="SizingContainer"> @if (!isBack) { @Html.Partial("List_CommandBar_Partial", Model) <div id="PostItemContainer" class="scrollbox" xstyle="-webkit-overflow-scrolling: touch;"> @Html.Partial("List_Items_Partial", Model) @if (Model.RequireLoadEntry) { <div class="postitem loadpostitems" style="padding: 15px;"> <div id="LoadProgress" class="smallprogressright"></div> <div class="control-progress"> Load additional listings... </div> </div> } </div> } </div> </form> As you can see the query string triggers a conditional block that if set is simply not rendered. The content inside of #SizingContainer basically holds  the entire page's HTML sans the headers and scripts, but including the filter options and menu at the top. In this case this makes good sense - in other situations the fact that the menu or filter options might be dynamically updated might make you only cache the list rather than essentially the entire page. In this particular instance all of the content works and produces the proper result as both the list along with any filter conditions in the form inputs are restored. Ok, let's move on to the client. On the client there are two page level functions that deal with saving and restoring state. Like the counter example I showed earlier, I like to wrap the logic to save and restore values from sessionState into a separate function because they are almost always used in several places.page.saveData = function(id) { if (!sessionStorage) return; var data = { id: id, scroll: $("#PostItemContainer").scrollTop(), html: $("#SizingContainer").html() }; sessionStorage.setItem("list_html",JSON.stringify(data)); }; page.restoreData = function() { if (!sessionStorage) return; var data = sessionStorage.getItem("list_html"); if (!data) return null; return JSON.parse(data); }; The data that is saved is an object which contains an ID which is the selected element when the user clicks and a scroll position. These two values are used to reset the scroll position when the data is used from the cache. Finally the html from the #SizingContainer element is stored, which makes for the bulk of the document's HTML. In this application the HTML captured could be a substantial bit of data. If you recall, I mentioned that the server side code renders a small chunk of data initially and then gets more data if the user reads through the first 50 or so items. The rest of the items retrieved can be rather sizable. Other than the JSON deserialization that's Ok. Since I'm using SessionStorage the storage space has no immediate limits. Next is the core logic to handle saving and restoring the page state. At first though this would seem pretty simple, and in some cases it might be, but as the following code demonstrates there are a few gotchas to watch out for. Here's the relevant code I use to save and restore:$( function() { … var isBack = getUrlEncodedKey("back", location.href); if (isBack) { // remove the back key from URL setUrlEncodedKey("back", "", location.href); var data = page.restoreData(); // restore from sessionState if (!data) { // no data - force redisplay of the server side default list window.location = "list"; return; } $("#SizingContainer").html(data.html); var el = $(".postitem[data-id=" + data.id + "]"); $(".postitem").removeClass("highlight"); el.addClass("highlight"); $("#PostItemContainer").scrollTop(data.scroll); setTimeout(function() { el.removeClass("highlight"); }, 2500); } else if (window.noFrames) page.saveData(null); // save when page loads $("#SizingContainer").on("click", ".postitem", function() { var id = $(this).attr("data-id"); if (!id) return true; if (window.noFrames) page.saveData(id); var contentFrame = window.parent.frames["Content"]; if (contentFrame) contentFrame.location.href = "show/" + id; else window.location.href = "show/" + id; return false; }); … The code starts out by checking for the back query string flag which triggers restoring from the client cache. If cached the cached data structure is read from sessionStorage. It's important here to check if data was returned. If the user had back=true on the querystring but there is no cached data, he likely bookmarked this page or otherwise shut down the browser and came back to this URL. In that case the server didn't render any detail and we have no cached data, so all we can do is redirect to the original default list view using window.location. If we continued the page would render no data - so make sure to always check the cache retrieval result. Always! If there is data the it's loaded and the data.html data is restored back into the document by simply injecting the HTML back into the document's #SizingContainer element:$("#SizingContainer").html(data.html); It's that simple and it's quite quick even with a fully loaded list of additional items and on a phone. The actual HTML data is stored to the cache on every page load initially and then again when the user clicks on an element to navigate to a particular listing. The former ensures that the client cache always has something in it, and the latter updates with additional information for the selected element. For the click handling I use a data-id attribute on the list item (.postitem) in the list and retrieve the id from that. That id is then used to navigate to the actual entry as well as storing that Id value in the saved cached data. The id is used to reset the selection by searching for the data-id value in the restored elements. The overall process of this save/restore process is pretty straight forward and it doesn't require a bunch of code, yet it yields a huge improvement in the usability of the site on mobile devices (or anybody who uses the non-frames view). Some things to watch out for As easy as it conceptually seems to simply store and retrieve cached content, you have to be quite aware what type of content you are caching. The code above is all that's specific to cache/restore cycle and it works, but it took a few tweaks to the rest of the script code and server code to make it all work. There were a few gotchas that weren't immediately obvious. Here are a few things to pay attention to: Event Handling Logic Timing of manipulating DOM events Inline Script Code Bookmarking to the Cache Url when no cache exists Do you have inline script code in your HTML? That script code isn't going to run if you restore from cache and simply assign or it may not run at the time you think it would normally in the DOM rendering cycle. JavaScript Event Hookups The biggest issue I ran into with this approach almost immediately is that originally I had various static event handlers hooked up to various UI elements that are now cached. If you have an event handler like:$("#btnSearch").click( function() {…}); that works fine when the page loads with server rendered HTML, but that code breaks when you now load the HTML from cache. Why? Because the elements you're trying to hook those events to may not actually be there - yet. Luckily there's an easy workaround for this by using deferred events. With jQuery you can use the .on() event handler instead:$("#SelectionContainer").on("click","#btnSearch", function() {…}); which monitors a parent element for the events and checks for the inner selector elements to handle events on. This effectively defers to runtime event binding, so as more items are added to the document bindings still work. For any cached content use deferred events. Timing of manipulating DOM Elements Along the same lines make sure that your DOM manipulation code follows the code that loads the cached content into the page so that you don't manipulate DOM elements that don't exist just yet. Ideally you'll want to check for the condition to restore cached content towards the top of your script code, but that can be tricky if you have components or other logic that might not all run in a straight line. Inline Script Code Here's another small problem I ran into: I use a DateTime Picker widget I built a while back that relies on the jQuery date time picker. I also created a helper function that allows keyboard date navigation into it that uses JavaScript logic. Because MVC's limited 'object model' the only way to embed widget content into the page is through inline script. This code broken when I inserted the cached HTML into the page because the script code was not available when the component actually got injected into the page. As the last bullet - it's a matter of timing. There's no good work around for this - in my case I pulled out the jQuery date picker and relied on native <input type="date" /> logic instead - a better choice these days anyway, especially since this view is meant to be primarily to serve mobile devices which actually support date input through the browser (unlike desktop browsers of which only WebKit seems to support it). Bookmarking Cached Urls When you cache HTML content you have to make a decision whether you cache on the client and also not render that same content on the server. In the Classifieds app I didn't render server side content so if the user comes to the page with back=True and there is no cached content I have to a have a Plan B. Typically this happens when somebody ends up bookmarking the back URL. The easiest and safest solution for this scenario is to ALWAYS check the cache result to make sure it exists and if not have a safe URL to go back to - in this case to the plain uncached list URL which amounts to effectively redirecting. This seems really obvious in hindsight, but it's easy to overlook and not see a problem until much later, when it's not obvious at all why the page is not rendering anything. Don't use <body> to replace Content Since we're practically replacing all the HTML in the page it may seem tempting to simply replace the HTML content of the <body> tag. Don't. The body tag usually contains key things that should stay in the page and be there when it loads. Specifically script tags and elements and possibly other embedded content. It's best to create a top level DOM element specifically as a placeholder container for your cached content and wrap just around the actual content you want to replace. In the app above the #SizingContainer is that container. Other Approaches The approach I've used for this application is kind of specific to the existing server rendered application we're running and so it's just one approach you can take with caching. However for server rendered content caching this is a pattern I've used in a few apps to retrofit some client caching into list displays. In this application I took the path of least resistance to the existing server rendering logic. Here are a few other ways that come to mind: Using Partial HTML Rendering via AJAXInstead of rendering the page initially on the server, the page would load empty and the client would render the UI by retrieving the respective HTML and embedding it into the page from a Partial View. This effectively makes the initial rendering and the cached rendering logic identical and removes the server having to decide whether this request needs to be rendered or not (ie. not checking for a back=true switch). All the logic related to caching is made on the client in this case. Using JSON Data and Client RenderingThe hardcore client option is to do the whole UI SPA style and pull data from the server and then use client rendering or databinding to pull the data down and render using templates or client side databinding with knockout/angular et al. As with the Partial Rendering approach the advantage is that there's no difference in the logic between pulling the data from cache or rendering from scratch other than the initial check for the cache request. Of course if the app is a  full on SPA app, then caching may not be required even - the list could just stay in memory and be hidden and reactivated. I'm sure there are a number of other ways this can be handled as well especially using  AJAX. AJAX rendering might simplify the logic, but it also complicates search engine optimization since there's no content loaded initially. So there are always tradeoffs and it's important to look at all angles before deciding on any sort of caching solution in general. State of the Session SessionState and LocalStorage are easy to use in client code and can be integrated even with server centric applications to provide nice caching features of content and data. In this post I've shown a very specific scenario of storing HTML content for the purpose of remembering list view data and state and making the browsing experience for lists a bit more friendly, especially if there's dynamically loaded content involved. If you haven't played with sessionStorage or localStorage I encourage you to give it a try. There's a lot of cool stuff that you can do with this beyond the specific scenario I've covered here… Resources Overview of localStorage (also applies to sessionStorage) Web Storage Compatibility Modernizr Test Suite© Rick Strahl, West Wind Technologies, 2005-2013Posted in JavaScript  HTML5  ASP.NET  MVC   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

  Read the article

• WD MBWE II (White Strip Light) 2TB - unable to access data

  - by user210477

  I have a WD MBWE II (White Strip Light) 2TB - (WD20000H2NC-00) Was working fine until a few days ago. I guess there was a power failure and after that I am unable to access the 'Public' or the 'Download' folder anymore. I have been searching for answers everywhere but came up empty handed. Web GUI still works, SSH works. I hooked up both the drives on my PC and UFS Explorer sees the drive. But so far I am unable to retrieve any of my data. I do not remember what RAID setting I used when I first got the drive. I can see from GUI that it is set as "Stripe". The drive contains 10 years of family pictures which I really do not want to loose. Sadly and stupidly, I didn't even keep a backup of this drive. Can somebody please help or point me in the right direction. Thank you in advance for your help. Disk Utility on Ubuntu reports 1405 bad sectors on one drive. How can I retrieve my data? Please help. Logs below: ~ # mdadm --detail /dev/md[012345678] /dev/md0: Version : 0.90 Creation Time : Wed Jul 15 08:36:17 2009 Raid Level : raid1 Array Size : 1959872 (1914.26 MiB 2006.91 MB) Used Dev Size : 1959872 (1914.26 MiB 2006.91 MB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 0 Persistence : Superblock is persistent Update Time : Fri Nov 1 13:53:29 2013 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 04f7a661:98983b3b:26b29e4f:9b646adb Events : 0.266 Number Major Minor RaidDevice State 0 8 1 0 active sync /dev/sda1 1 8 17 1 active sync /dev/sdb1 /dev/md1: Version : 0.90 Creation Time : Wed Jul 15 08:36:18 2009 Raid Level : raid1 Array Size : 256896 (250.92 MiB 263.06 MB) Used Dev Size : 256896 (250.92 MiB 263.06 MB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 1 Persistence : Superblock is persistent Update Time : Wed Oct 30 22:08:21 2013 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : aaa7b859:c475312d:efc5a766:6526b867 Events : 0.10 Number Major Minor RaidDevice State 0 8 2 0 active sync /dev/sda2 1 8 18 1 active sync /dev/sdb2 /dev/md2: Version : 0.90 Creation Time : Sat Sep 25 10:01:26 2010 Raid Level : raid0 Array Size : 1947045760 (1856.85 GiB 1993.77 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Fri Nov 1 13:30:53 2013 State : active Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Chunk Size : 64K UUID : 01dae60a:6831077b:77f74530:8680c183 Events : 0.97 Number Major Minor RaidDevice State 0 8 4 0 active sync /dev/sda4 1 8 20 1 active sync /dev/sdb4 /dev/md3: Version : 0.90 Creation Time : Wed Jul 15 08:36:18 2009 Raid Level : raid1 Array Size : 987904 (964.91 MiB 1011.61 MB) Used Dev Size : 987904 (964.91 MiB 1011.61 MB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 3 Persistence : Superblock is persistent Update Time : Fri Nov 1 13:26:33 2013 State : clean Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 UUID : 3f4099f2:72e6171b:5ba962fd:48464a62 Events : 0.54 Number Major Minor RaidDevice State 0 8 3 0 active sync /dev/sda3 1 8 19 1 active sync /dev/sdb3 mdadm: md device /dev/md4 does not appear to be active. mdadm: md device /dev/md5 does not appear to be active. mdadm: md device /dev/md6 does not appear to be active. mdadm: md device /dev/md7 does not appear to be active. mdadm: md device /dev/md8 does not appear to be active. ~ # cat /etc/mtab securityfs /sys/kernel/security securityfs rw 0 0 /dev/md2 /DataVolume xfs rw,usrquota 0 0 /dev/md4 /ExtendVolume xfs rw,usrquota 0 0 ~ # df -k Filesystem 1k-blocks Used Available Use% Mounted on /dev/md0 1929044 145092 1685960 8% / /dev/md3 972344 123452 799500 13% /var /dev/ram0 63412 20 63392 0% /mnt/ram ~ # mdadm -D /dev/md2 /dev/md2: Version : 0.90 Creation Time : Sat Sep 25 10:01:26 2010 Raid Level : raid0 Array Size : 1947045760 (1856.85 GiB 1993.77 GB) Raid Devices : 2 Total Devices : 2 Preferred Minor : 2 Persistence : Superblock is persistent Update Time : Fri Nov 1 13:30:53 2013 State : active Active Devices : 2 Working Devices : 2 Failed Devices : 0 Spare Devices : 0 Chunk Size : 64K UUID : 01dae60a:6831077b:77f74530:8680c183 Events : 0.97 Number Major Minor RaidDevice State 0 8 4 0 active sync /dev/sda4 1 8 20 1 active sync /dev/sdb4 ~ # mdadm -D /dev/md4 mdadm: md device /dev/md4 does not appear to be active. ~ # mount /dev/root on / type ext3 (rw,noatime,data=ordered) proc on /proc type proc (rw) sys on /sys type sysfs (rw) /dev/pts on /dev/pts type devpts (rw) securityfs on /sys/kernel/security type securityfs (rw) /dev/md3 on /var type ext3 (rw,noatime,data=ordered) /dev/ram0 on /mnt/ram type tmpfs (rw) ~ # cat /var/log/messages Oct 29 18:04:50 shmotashNAS daemon.warn wixEvent[3462]: Network Link - NIC 1 link is down. Oct 29 18:04:59 shmotashNAS daemon.info wixEvent[3462]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 29 18:04:59 shmotashNAS daemon.info wixEvent[3462]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 29 18:17:45 shmotashNAS daemon.warn wixEvent[3462]: Network Link - NIC 1 link is down. Oct 29 18:17:53 shmotashNAS daemon.info wixEvent[3462]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 29 18:17:53 shmotashNAS daemon.info wixEvent[3462]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 00:50:11 shmotashNAS daemon.warn wixEvent[3462]: Network Link - NIC 1 link is down. Oct 30 00:50:19 shmotashNAS daemon.info wixEvent[3462]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 00:50:19 shmotashNAS daemon.info wixEvent[3462]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 16:29:47 shmotashNAS daemon.warn wixEvent[3462]: Network Link - NIC 1 link is down. Oct 30 16:30:00 shmotashNAS daemon.info wixEvent[3462]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 16:30:00 shmotashNAS daemon.info wixEvent[3462]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 18:27:22 shmotashNAS daemon.warn wixEvent[3462]: Network Link - NIC 1 link is down. Oct 30 18:27:30 shmotashNAS daemon.info wixEvent[3462]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 18:27:30 shmotashNAS daemon.info wixEvent[3462]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 19:06:03 shmotashNAS daemon.warn wixEvent[3462]: Network Link - NIC 1 link is down. Oct 30 19:06:10 shmotashNAS daemon.info wixEvent[3462]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 19:06:10 shmotashNAS daemon.info wixEvent[3462]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 19:14:58 shmotashNAS daemon.warn wixEvent[3462]: Media Server - Media Server cannot find the path to one or more of the default folders: /Public/Shared Music, /Public/Shared Pictures or /Public/Shared Videos. Please verify that these folders have not been removed or that the names have not been changed. Oct 30 19:20:05 shmotashNAS daemon.alert wixEvent[3462]: Thermal Alarm - System temperature exceeded threshold.(66 degrees) Oct 30 19:58:29 shmotashNAS daemon.alert wixEvent[3462]: HDD SMART - HDD 1 SMART Health Status: Failed. Oct 30 22:05:39 shmotashNAS daemon.info init: Starting pid 13043, console /dev/null: '/usr/bin/killall' Oct 30 22:05:39 shmotashNAS syslog.info System log daemon exiting. Oct 30 22:08:09 shmotashNAS syslog.info syslogd started: BusyBox v1.1.1 Oct 30 22:08:09 shmotashNAS daemon.warn wixEvent[3557]: Network Link - NIC 1 link is down. Oct 30 22:08:19 shmotashNAS daemon.info wixEvent[3557]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 22:08:25 shmotashNAS daemon.warn wixEvent[3557]: Network Link - NIC 1 link is down. Oct 30 22:08:37 shmotashNAS daemon.info wixEvent[3557]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 22:08:44 shmotashNAS daemon.warn wixEvent[3557]: Network Link - NIC 1 link is down. Oct 30 22:08:46 shmotashNAS syslog.info miocrawler: +++++++++++++++ START OF ./miocrawler at 2013:10:30 - 22:08:46 [Version 01.09.00.96] ++++++++++++++ Oct 30 22:08:46 shmotashNAS syslog.info miocrawler: mc_db_init ... Oct 30 22:08:46 shmotashNAS syslog.info miocrawler: ****** database does not exist. ret = -1, creating path Oct 30 22:08:49 shmotashNAS syslog.info miocrawler: === mc_db_init ...Done. Oct 30 22:08:50 shmotashNAS syslog.info miocrawler: mcUtilsInit() Creating free queue pool Oct 30 22:08:51 shmotashNAS syslog.info miocrawler: === mcUtilsInit() Done. Oct 30 22:08:51 shmotashNAS syslog.info miocrawler: === inotify init done. Oct 30 22:08:51 shmotashNAS syslog.info miocrawler: mc_trans_updater_init() ... Oct 30 22:08:52 shmotashNAS syslog.info miocrawler: === mc_trans_updater_init() ...Done. Oct 30 22:08:52 shmotashNAS syslog.info miocrawler: === Walking directory done. Oct 30 22:08:57 shmotashNAS daemon.info wixEvent[3557]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 22:08:57 shmotashNAS daemon.info wixEvent[3557]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 22:08:57 shmotashNAS daemon.info wixEvent[3557]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 22:08:57 shmotashNAS daemon.info wixEvent[3557]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 22:09:10 shmotashNAS daemon.info init: Starting pid 4605, console /dev/null: '/bin/touch' Oct 30 22:09:10 shmotashNAS daemon.info init: Starting pid 4607, console /dev/ttyS0: '/sbin/getty' Oct 30 22:09:10 shmotashNAS daemon.info wixEvent[3557]: System Startup - System startup. Oct 30 22:09:16 shmotashNAS daemon.warn wixEvent[3557]: Media Server - Media Server cannot find the path to one or more of the default folders: /Public/Shared Music, /Public/Shared Pictures or /Public/Shared Videos. Please verify that these folders have not been removed or that the names have not been changed. Oct 30 22:14:14 shmotashNAS daemon.warn wixEvent[3557]: Network Link - NIC 1 link is down. Oct 30 22:14:21 shmotashNAS daemon.info wixEvent[3557]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 22:14:21 shmotashNAS daemon.info wixEvent[3557]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 22:29:36 shmotashNAS daemon.warn wixEvent[3557]: System Reboot - System will reboot. Oct 30 22:29:40 shmotashNAS daemon.info init: Starting pid 5974, console /dev/null: '/usr/bin/killall' Oct 30 22:29:40 shmotashNAS syslog.info System log daemon exiting. Oct 30 22:47:56 shmotashNAS syslog.info syslogd started: BusyBox v1.1.1 Oct 30 22:47:56 shmotashNAS daemon.warn wixEvent[3461]: Network Link - NIC 1 link is down. Oct 30 22:48:02 shmotashNAS daemon.info wixEvent[3461]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 22:48:02 shmotashNAS daemon.info wixEvent[3461]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 22:48:09 shmotashNAS syslog.info miocrawler: +++++++++++++++ START OF ./miocrawler at 2013:10:30 - 22:48:09 [Version 01.09.00.96] ++++++++++++++ Oct 30 22:48:09 shmotashNAS syslog.info miocrawler: mc_db_init ... Oct 30 22:48:09 shmotashNAS syslog.info miocrawler: ++++++++ database exists: ret = 0 Oct 30 22:48:10 shmotashNAS syslog.info miocrawler: === mc_db_init ...Done. Oct 30 22:48:10 shmotashNAS syslog.info miocrawler: mcUtilsInit() Creating free queue pool Oct 30 22:48:11 shmotashNAS syslog.info miocrawler: === mcUtilsInit() Done. Oct 30 22:48:11 shmotashNAS syslog.info miocrawler: === inotify init done. Oct 30 22:48:11 shmotashNAS syslog.info miocrawler: mc_trans_updater_init() ... Oct 30 22:48:11 shmotashNAS syslog.info miocrawler: === mc_trans_updater_init() ...Done. Oct 30 22:48:11 shmotashNAS syslog.info miocrawler: === Walking directory done. Oct 30 22:48:27 shmotashNAS daemon.info init: Starting pid 4079, console /dev/null: '/bin/touch' Oct 30 22:48:27 shmotashNAS daemon.info init: Starting pid 4080, console /dev/ttyS0: '/sbin/getty' Oct 30 22:48:28 shmotashNAS daemon.info wixEvent[3461]: System Startup - System startup. Oct 30 22:49:01 shmotashNAS daemon.warn wixEvent[3461]: Media Server - Media Server cannot find the path to one or more of the default folders: /Public/Shared Music, /Public/Shared Pictures or /Public/Shared Videos. Please verify that these folders have not been removed or that the names have not been changed. Oct 30 23:51:11 shmotashNAS daemon.warn wixEvent[3461]: System Reboot - System will reboot. Oct 30 23:51:16 shmotashNAS daemon.info init: Starting pid 6498, console /dev/null: '/usr/bin/killall' Oct 30 23:51:16 shmotashNAS syslog.info System log daemon exiting. Oct 30 23:54:19 shmotashNAS syslog.info syslogd started: BusyBox v1.1.1 Oct 30 23:55:37 shmotashNAS daemon.info wixEvent[3476]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 30 23:55:37 shmotashNAS daemon.info wixEvent[3476]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 30 23:55:44 shmotashNAS syslog.info miocrawler: +++++++++++++++ START OF ./miocrawler at 2013:10:30 - 23:55:44 [Version 01.09.00.96] ++++++++++++++ Oct 30 23:55:44 shmotashNAS syslog.info miocrawler: mc_db_init ... Oct 30 23:55:44 shmotashNAS syslog.info miocrawler: ++++++++ database exists: ret = 0 Oct 30 23:55:45 shmotashNAS syslog.info miocrawler: === mc_db_init ...Done. Oct 30 23:55:45 shmotashNAS syslog.info miocrawler: mcUtilsInit() Creating free queue pool Oct 30 23:55:46 shmotashNAS syslog.info miocrawler: === mcUtilsInit() Done. Oct 30 23:55:46 shmotashNAS syslog.info miocrawler: === inotify init done. Oct 30 23:55:46 shmotashNAS syslog.info miocrawler: mc_trans_updater_init() ... Oct 30 23:55:46 shmotashNAS syslog.info miocrawler: === mc_trans_updater_init() ...Done. Oct 30 23:55:46 shmotashNAS syslog.info miocrawler: === Walking directory done. Oct 30 23:55:58 shmotashNAS daemon.info init: Starting pid 4115, console /dev/null: '/bin/touch' Oct 30 23:55:58 shmotashNAS daemon.info init: Starting pid 4116, console /dev/ttyS0: '/sbin/getty' Oct 30 23:55:58 shmotashNAS daemon.info wixEvent[3476]: System Startup - System startup. Oct 30 23:56:33 shmotashNAS daemon.warn wixEvent[3476]: Media Server - Media Server cannot find the path to one or more of the default folders: /Public/Shared Music, /Public/Shared Pictures or /Public/Shared Videos. Please verify that these folders have not been removed or that the names have not been changed. Oct 31 00:29:14 shmotashNAS auth.info sshd[5409]: Server listening on 0.0.0.0 port 22. Oct 31 00:31:25 shmotashNAS auth.info sshd[5486]: Accepted password for root from 192.168.1.100 port 50785 ssh2 Oct 31 00:33:44 shmotashNAS auth.info sshd[5565]: Accepted password for root from 192.168.1.100 port 50817 ssh2 Oct 31 00:36:39 shmotashNAS daemon.info init: Starting pid 5680, console /dev/null: '/usr/bin/killall' Oct 31 00:36:39 shmotashNAS syslog.info System log daemon exiting. Oct 31 00:40:44 shmotashNAS syslog.info syslogd started: BusyBox v1.1.1 Oct 31 00:40:51 shmotashNAS daemon.info wixEvent[3464]: Network Link - NIC 1 link is up 100 Mbps full duplex. Oct 31 00:40:51 shmotashNAS daemon.info wixEvent[3464]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Oct 31 00:41:00 shmotashNAS syslog.info miocrawler: +++++++++++++++ START OF ./miocrawler at 2013:10:31 - 00:41:00 [Version 01.09.00.96] ++++++++++++++ Oct 31 00:41:00 shmotashNAS syslog.info miocrawler: mc_db_init ... Oct 31 00:41:00 shmotashNAS syslog.info miocrawler: ++++++++ database exists: ret = 0 Oct 31 00:41:00 shmotashNAS syslog.info miocrawler: === mc_db_init ...Done. Oct 31 00:41:01 shmotashNAS syslog.info miocrawler: mcUtilsInit() Creating free queue pool Oct 31 00:41:02 shmotashNAS syslog.info miocrawler: === mcUtilsInit() Done. Oct 31 00:41:02 shmotashNAS syslog.info miocrawler: === inotify init done. Oct 31 00:41:02 shmotashNAS syslog.info miocrawler: mc_trans_updater_init() ... Oct 31 00:41:02 shmotashNAS syslog.info miocrawler: === mc_trans_updater_init() ...Done. Oct 31 00:41:02 shmotashNAS syslog.info miocrawler: === Walking directory done. Oct 31 00:41:14 shmotashNAS daemon.info init: Starting pid 4101, console /dev/null: '/bin/touch' Oct 31 00:41:14 shmotashNAS daemon.info init: Starting pid 4102, console /dev/ttyS0: '/sbin/getty' Oct 31 00:41:15 shmotashNAS daemon.info wixEvent[3464]: System Startup - System startup. Oct 31 00:41:47 shmotashNAS daemon.warn wixEvent[3464]: Media Server - Media Server cannot find the path to one or more of the default folders: /Public/Shared Music, /Public/Shared Pictures or /Public/Shared Videos. Please verify that these folders have not been removed or that the names have not been changed. Oct 31 01:13:19 shmotashNAS daemon.info init: Starting pid 5385, console /dev/null: '/usr/bin/killall' Oct 31 01:13:19 shmotashNAS syslog.info System log daemon exiting. Nov 1 13:26:25 shmotashNAS syslog.info syslogd started: BusyBox v1.1.1 Nov 1 13:26:32 shmotashNAS daemon.info wixEvent[3471]: Network Link - NIC 1 link is up 100 Mbps full duplex. Nov 1 13:26:32 shmotashNAS daemon.info wixEvent[3471]: Network IP Address - NIC 1 use static IP address 192.168.1.102 Nov 1 13:26:38 shmotashNAS syslog.info miocrawler: +++++++++++++++ START OF ./miocrawler at 2013:11:01 - 13:26:38 [Version 01.09.00.96] ++++++++++++++ Nov 1 13:26:38 shmotashNAS syslog.info miocrawler: mc_db_init ... Nov 1 13:26:38 shmotashNAS syslog.info miocrawler: ++++++++ database exists: ret = 0 Nov 1 13:26:39 shmotashNAS syslog.info miocrawler: === mc_db_init ...Done. Nov 1 13:26:39 shmotashNAS syslog.info miocrawler: mcUtilsInit() Creating free queue pool Nov 1 13:26:40 shmotashNAS syslog.info miocrawler: === mcUtilsInit() Done. Nov 1 13:26:40 shmotashNAS syslog.info miocrawler: === inotify init done. Nov 1 13:26:40 shmotashNAS syslog.info miocrawler: mc_trans_updater_init() ... Nov 1 13:26:40 shmotashNAS syslog.info miocrawler: === mc_trans_updater_init() ...Done. Nov 1 13:26:40 shmotashNAS syslog.info miocrawler: === Walking directory done. Nov 1 13:26:52 shmotashNAS daemon.info init: Starting pid 4078, console /dev/null: '/bin/touch' Nov 1 13:26:52 shmotashNAS daemon.info init: Starting pid 4079, console /dev/ttyS0: '/sbin/getty' Nov 1 13:26:52 shmotashNAS daemon.info wixEvent[3471]: System Startup - System startup. Nov 1 13:27:28 shmotashNAS daemon.warn wixEvent[3471]: Media Server - Media Server cannot find the path to one or more of the default folders: /Public/Shared Music, /Public/Shared Pictures or /Public/Shared Videos. Please verify that these folders have not been removed or that the names have not been changed. Nov 1 13:44:48 shmotashNAS auth.info sshd[5375]: Accepted password for root from 192.168.1.103 port 50217 ssh2 Nov 1 13:51:08 shmotashNAS auth.info sshd[5894]: Accepted password for root from 192.168.1.103 port 50380 ssh2

  Read the article

• Silverlight Recruiting Application Part 5 - Jobs Module / View

  Now we starting getting into a more code-heavy portion of this series, thankfully though this means the groundwork is all set for the most part and after adding the modules we will have a complete application that can be provided with full source. The Jobs module will have two concerns- adding and maintaining jobs that can then be broadcast out to the website. How they are displayed on the site will be handled by our admin system (which will just poll from this common database), so we aren't too concerned with that, but rather with getting the information into the system and allowing the backend administration/HR users to keep things up to date. Since there is a fair bit of information that we want to display, we're going to move editing to a separate view so we can get all that information in an easy-to-use spot. With all the files created for this module, the project looks something like this: And now... on to the code. XAML for the Job Posting View All we really need for the Job Posting View is a RadGridView and a few buttons. This will let us both show off records and perform operations on the records without much hassle. That XAML is going to look something like this: 01.<Grid x:Name="LayoutRoot" 02.Background="White"> 03.<Grid.RowDefinitions> 04.<RowDefinition Height="30" /> 05.<RowDefinition /> 06.</Grid.RowDefinitions> 07.<StackPanel Orientation="Horizontal"> 08.<Button x:Name="xAddRecordButton" 09.Content="Add Job" 10.Width="120" 11.cal:Click.Command="{Binding AddRecord}" 12.telerik:StyleManager.Theme="Windows7" /> 13.<Button x:Name="xEditRecordButton" 14.Content="Edit Job" 15.Width="120" 16.cal:Click.Command="{Binding EditRecord}" 17.telerik:StyleManager.Theme="Windows7" /> 18.</StackPanel> 19.<telerikGrid:RadGridView x:Name="xJobsGrid" 20.Grid.Row="1" 21.IsReadOnly="True" 22.AutoGenerateColumns="False" 23.ColumnWidth="*" 24.RowDetailsVisibilityMode="VisibleWhenSelected" 25.ItemsSource="{Binding MyJobs}" 26.SelectedItem="{Binding SelectedJob, Mode=TwoWay}" 27.command:SelectedItemChangedEventClass.Command="{Binding SelectedItemChanged}"> 28.<telerikGrid:RadGridView.Columns> 29.<telerikGrid:GridViewDataColumn Header="Job Title" 30.DataMemberBinding="{Binding JobTitle}" 31.UniqueName="JobTitle" /> 32.<telerikGrid:GridViewDataColumn Header="Location" 33.DataMemberBinding="{Binding Location}" 34.UniqueName="Location" /> 35.<telerikGrid:GridViewDataColumn Header="Resume Required" 36.DataMemberBinding="{Binding NeedsResume}" 37.UniqueName="NeedsResume" /> 38.<telerikGrid:GridViewDataColumn Header="CV Required" 39.DataMemberBinding="{Binding NeedsCV}" 40.UniqueName="NeedsCV" /> 41.<telerikGrid:GridViewDataColumn Header="Overview Required" 42.DataMemberBinding="{Binding NeedsOverview}" 43.UniqueName="NeedsOverview" /> 44.<telerikGrid:GridViewDataColumn Header="Active" 45.DataMemberBinding="{Binding IsActive}" 46.UniqueName="IsActive" /> 47.</telerikGrid:RadGridView.Columns> 48.</telerikGrid:RadGridView> 49.</Grid> I'll explain what's happening here by line numbers: Lines 11 and 16: Using the same type of click commands as we saw in the Menu module, we tie the button clicks to delegate commands in the viewmodel. Line 25: The source for the jobs will be a collection in the viewmodel. Line 26: We also bind the selected item to a public property from the viewmodel for use in code. Line 27: We've turned the event into a command so we can handle it via code in the viewmodel. So those first three probably make sense to you as far as Silverlight/WPF binding magic is concerned, but for line 27... This actually comes from something I read onDamien Schenkelman's blog back in the day for creating an attached behavior from any event. So, any time you see me using command:Whatever.Command, the backing for it is actually something like this: SelectedItemChangedEventBehavior.cs: 01.public class SelectedItemChangedEventBehavior : CommandBehaviorBase<Telerik.Windows.Controls.DataControl> 02.{ 03.public SelectedItemChangedEventBehavior(DataControl element) 04.: base(element) 05.{ 06.element.SelectionChanged += new EventHandler<SelectionChangeEventArgs>(element_SelectionChanged); 07.} 08.void element_SelectionChanged(object sender, SelectionChangeEventArgs e) 09.{ 10.// We'll only ever allow single selection, so will only need item index 0 11.base.CommandParameter = e.AddedItems[0]; 12.base.ExecuteCommand(); 13.} 14.} SelectedItemChangedEventClass.cs: 01.public class SelectedItemChangedEventClass 02.{ 03.#region The Command Stuff 04.public static ICommand GetCommand(DependencyObject obj) 05.{ 06.return (ICommand)obj.GetValue(CommandProperty); 07.} 08.public static void SetCommand(DependencyObject obj, ICommand value) 09.{ 10.obj.SetValue(CommandProperty, value); 11.} 12.public static readonly DependencyProperty CommandProperty = 13.DependencyProperty.RegisterAttached("Command", typeof(ICommand), 14.typeof(SelectedItemChangedEventClass), new PropertyMetadata(OnSetCommandCallback)); 15.public static void OnSetCommandCallback(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) 16.{ 17.DataControl element = dependencyObject as DataControl; 18.if (element != null) 19.{ 20.SelectedItemChangedEventBehavior behavior = GetOrCreateBehavior(element); 21.behavior.Command = e.NewValue as ICommand; 22.} 23.} 24.#endregion 25.public static SelectedItemChangedEventBehavior GetOrCreateBehavior(DataControl element) 26.{ 27.SelectedItemChangedEventBehavior behavior = element.GetValue(SelectedItemChangedEventBehaviorProperty) as SelectedItemChangedEventBehavior; 28.if (behavior == null) 29.{ 30.behavior = new SelectedItemChangedEventBehavior(element); 31.element.SetValue(SelectedItemChangedEventBehaviorProperty, behavior); 32.} 33.return behavior; 34.} 35.public static SelectedItemChangedEventBehavior GetSelectedItemChangedEventBehavior(DependencyObject obj) 36.{ 37.return (SelectedItemChangedEventBehavior)obj.GetValue(SelectedItemChangedEventBehaviorProperty); 38.} 39.public static void SetSelectedItemChangedEventBehavior(DependencyObject obj, SelectedItemChangedEventBehavior value) 40.{ 41.obj.SetValue(SelectedItemChangedEventBehaviorProperty, value); 42.} 43.public static readonly DependencyProperty SelectedItemChangedEventBehaviorProperty = 44.DependencyProperty.RegisterAttached("SelectedItemChangedEventBehavior", 45.typeof(SelectedItemChangedEventBehavior), typeof(SelectedItemChangedEventClass), null); 46.} These end up looking very similar from command to command, but in a nutshell you create a command based on any event, determine what the parameter for it will be, then execute. It attaches via XAML and ties to a DelegateCommand in the viewmodel, so you get the full event experience (since some controls get a bit event-rich for added functionality). Simple enough, right? Viewmodel for the Job Posting View The Viewmodel is going to need to handle all events going back and forth, maintaining interactions with the data we are using, and both publishing and subscribing to events. Rather than breaking this into tons of little pieces, I'll give you a nice view of the entire viewmodel and then hit up the important points line-by-line: 001.public class JobPostingViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005.public DelegateCommand<object> AddRecord { get; set; } 006.public DelegateCommand<object> EditRecord { get; set; } 007.public DelegateCommand<object> SelectedItemChanged { get; set; } 008.public RecruitingContext context; 009.private QueryableCollectionView _myJobs; 010.public QueryableCollectionView MyJobs 011.{ 012.get { return _myJobs; } 013.} 014.private QueryableCollectionView _selectionJobActionHistory; 015.public QueryableCollectionView SelectedJobActionHistory 016.{ 017.get { return _selectionJobActionHistory; } 018.} 019.private JobPosting _selectedJob; 020.public JobPosting SelectedJob 021.{ 022.get { return _selectedJob; } 023.set 024.{ 025.if (value != _selectedJob) 026.{ 027._selectedJob = value; 028.NotifyChanged("SelectedJob"); 029.} 030.} 031.} 032.public SubscriptionToken editToken = new SubscriptionToken(); 033.public SubscriptionToken addToken = new SubscriptionToken(); 034.public JobPostingViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 035.{ 036.// set Unity items 037.this.eventAggregator = eventAgg; 038.this.regionManager = regionmanager; 039.// load our context 040.context = new RecruitingContext(); 041.this._myJobs = new QueryableCollectionView(context.JobPostings); 042.context.Load(context.GetJobPostingsQuery()); 043.// set command events 044.this.AddRecord = new DelegateCommand<object>(this.AddNewRecord); 045.this.EditRecord = new DelegateCommand<object>(this.EditExistingRecord); 046.this.SelectedItemChanged = new DelegateCommand<object>(this.SelectedRecordChanged); 047.SetSubscriptions(); 048.} 049.#region DelegateCommands from View 050.public void AddNewRecord(object obj) 051.{ 052.this.eventAggregator.GetEvent<AddJobEvent>().Publish(true); 053.} 054.public void EditExistingRecord(object obj) 055.{ 056.if (_selectedJob == null) 057.{ 058.this.eventAggregator.GetEvent<NotifyUserEvent>().Publish("No job selected."); 059.} 060.else 061.{ 062.this._myJobs.EditItem(this._selectedJob); 063.this.eventAggregator.GetEvent<EditJobEvent>().Publish(this._selectedJob); 064.} 065.} 066.public void SelectedRecordChanged(object obj) 067.{ 068.if (obj.GetType() == typeof(ActionHistory)) 069.{ 070.// event bubbles up so we don't catch items from the ActionHistory grid 071.} 072.else 073.{ 074.JobPosting job = obj as JobPosting; 075.GrabHistory(job.PostingID); 076.} 077.} 078.#endregion 079.#region Subscription Declaration and Events 080.public void SetSubscriptions() 081.{ 082.EditJobCompleteEvent editComplete = eventAggregator.GetEvent<EditJobCompleteEvent>(); 083.if (editToken != null) 084.editComplete.Unsubscribe(editToken); 085.editToken = editComplete.Subscribe(this.EditCompleteEventHandler); 086.AddJobCompleteEvent addComplete = eventAggregator.GetEvent<AddJobCompleteEvent>(); 087.if (addToken != null) 088.addComplete.Unsubscribe(addToken); 089.addToken = addComplete.Subscribe(this.AddCompleteEventHandler); 090.} 091.public void EditCompleteEventHandler(bool complete) 092.{ 093.if (complete) 094.{ 095.JobPosting thisJob = _myJobs.CurrentEditItem as JobPosting; 096.this._myJobs.CommitEdit(); 097.this.context.SubmitChanges((s) => 098.{ 099.ActionHistory myAction = new ActionHistory(); 100.myAction.PostingID = thisJob.PostingID; 101.myAction.Description = String.Format("Job '{0}' has been edited by {1}", thisJob.JobTitle, "default user"); 102.myAction.TimeStamp = DateTime.Now; 103.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 104.} 105., null); 106.} 107.else 108.{ 109.this._myJobs.CancelEdit(); 110.} 111.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 112.} 113.public void AddCompleteEventHandler(JobPosting job) 114.{ 115.if (job == null) 116.{ 117.// do nothing, new job add cancelled 118.} 119.else 120.{ 121.this.context.JobPostings.Add(job); 122.this.context.SubmitChanges((s) => 123.{ 124.ActionHistory myAction = new ActionHistory(); 125.myAction.PostingID = job.PostingID; 126.myAction.Description = String.Format("Job '{0}' has been added by {1}", job.JobTitle, "default user"); 127.myAction.TimeStamp = DateTime.Now; 128.eventAggregator.GetEvent<AddActionEvent>().Publish(myAction); 129.} 130., null); 131.} 132.this.MakeMeActive(this.regionManager, "MainRegion", "JobPostingsView"); 133.} 134.#endregion 135.public void GrabHistory(int postID) 136.{ 137.context.ActionHistories.Clear(); 138._selectionJobActionHistory = new QueryableCollectionView(context.ActionHistories); 139.context.Load(context.GetHistoryForJobQuery(postID)); 140.} Taking it from the top, we're injecting an Event Aggregator and Region Manager for use down the road and also have the public DelegateCommands (just like in the Menu module). We also grab a reference to our context, which we'll obviously need for data, then set up a few fields with public properties tied to them. We're also setting subscription tokens, which we have not yet seen but I will get into below. The AddNewRecord (50) and EditExistingRecord (54) methods should speak for themselves for functionality, the one thing of note is we're sending events off to the Event Aggregator which some module, somewhere will take care of. Since these aren't entirely relying on one another, the Jobs View doesn't care if anyone is listening, but it will publish AddJobEvent (52), NotifyUserEvent (58) and EditJobEvent (63)regardless. Don't mind the GrabHistory() method so much, that is just grabbing history items (visibly being created in the SubmitChanges callbacks), and adding them to the database. Every action will trigger a history event, so we'll know who modified what and when, just in case. ;) So where are we at? Well, if we click to Add a job, we publish an event, if we edit a job, we publish an event with the selected record (attained through the magic of binding). Where is this all going though? To the Viewmodel, of course! XAML for the AddEditJobView This is pretty straightforward except for one thing, noted below: 001.<Grid x:Name="LayoutRoot" 002.Background="White"> 003.<Grid x:Name="xEditGrid" 004.Margin="10" 005.validationHelper:ValidationScope.Errors="{Binding Errors}"> 006.<Grid.Background> 007.<LinearGradientBrush EndPoint="0.5,1" 008.StartPoint="0.5,0"> 009.<GradientStop Color="#FFC7C7C7" 010.Offset="0" /> 011.<GradientStop Color="#FFF6F3F3" 012.Offset="1" /> 013.</LinearGradientBrush> 014.</Grid.Background> 015.<Grid.RowDefinitions> 016.<RowDefinition Height="40" /> 017.<RowDefinition Height="40" /> 018.<RowDefinition Height="40" /> 019.<RowDefinition Height="100" /> 020.<RowDefinition Height="100" /> 021.<RowDefinition Height="100" /> 022.<RowDefinition Height="40" /> 023.<RowDefinition Height="40" /> 024.<RowDefinition Height="40" /> 025.</Grid.RowDefinitions> 026.<Grid.ColumnDefinitions> 027.<ColumnDefinition Width="150" /> 028.<ColumnDefinition Width="150" /> 029.<ColumnDefinition Width="300" /> 030.<ColumnDefinition Width="100" /> 031.</Grid.ColumnDefinitions> 032.<!-- Title --> 033.<TextBlock Margin="8" 034.Text="{Binding AddEditString}" 035.TextWrapping="Wrap" 036.Grid.Column="1" 037.Grid.ColumnSpan="2" 038.FontSize="16" /> 039.<!-- Data entry area--> 040. 041.<TextBlock Margin="8,0,0,0" 042.Style="{StaticResource LabelTxb}" 043.Grid.Row="1" 044.Text="Job Title" 045.VerticalAlignment="Center" /> 046.<TextBox x:Name="xJobTitleTB" 047.Margin="0,8" 048.Grid.Column="1" 049.Grid.Row="1" 050.Text="{Binding activeJob.JobTitle, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 051.Grid.ColumnSpan="2" /> 052.<TextBlock Margin="8,0,0,0" 053.Grid.Row="2" 054.Text="Location" 055.d:LayoutOverrides="Height" 056.VerticalAlignment="Center" /> 057.<TextBox x:Name="xLocationTB" 058.Margin="0,8" 059.Grid.Column="1" 060.Grid.Row="2" 061.Text="{Binding activeJob.Location, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 062.Grid.ColumnSpan="2" /> 063. 064.<TextBlock Margin="8,11,8,0" 065.Grid.Row="3" 066.Text="Description" 067.TextWrapping="Wrap" 068.VerticalAlignment="Top" /> 069. 070.<TextBox x:Name="xDescriptionTB" 071.Height="84" 072.TextWrapping="Wrap" 073.ScrollViewer.VerticalScrollBarVisibility="Auto" 074.Grid.Column="1" 075.Grid.Row="3" 076.Text="{Binding activeJob.Description, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 077.Grid.ColumnSpan="2" /> 078.<TextBlock Margin="8,11,8,0" 079.Grid.Row="4" 080.Text="Requirements" 081.TextWrapping="Wrap" 082.VerticalAlignment="Top" /> 083. 084.<TextBox x:Name="xRequirementsTB" 085.Height="84" 086.TextWrapping="Wrap" 087.ScrollViewer.VerticalScrollBarVisibility="Auto" 088.Grid.Column="1" 089.Grid.Row="4" 090.Text="{Binding activeJob.Requirements, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 091.Grid.ColumnSpan="2" /> 092.<TextBlock Margin="8,11,8,0" 093.Grid.Row="5" 094.Text="Qualifications" 095.TextWrapping="Wrap" 096.VerticalAlignment="Top" /> 097. 098.<TextBox x:Name="xQualificationsTB" 099.Height="84" 100.TextWrapping="Wrap" 101.ScrollViewer.VerticalScrollBarVisibility="Auto" 102.Grid.Column="1" 103.Grid.Row="5" 104.Text="{Binding activeJob.Qualifications, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}" 105.Grid.ColumnSpan="2" /> 106.<!-- Requirements Checkboxes--> 107. 108.<CheckBox x:Name="xResumeRequiredCB" Margin="8,8,8,15" 109.Content="Resume Required" 110.Grid.Row="6" 111.Grid.ColumnSpan="2" 112.IsChecked="{Binding activeJob.NeedsResume, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 113. 114.<CheckBox x:Name="xCoverletterRequiredCB" Margin="8,8,8,15" 115.Content="Cover Letter Required" 116.Grid.Column="2" 117.Grid.Row="6" 118.IsChecked="{Binding activeJob.NeedsCV, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 119. 120.<CheckBox x:Name="xOverviewRequiredCB" Margin="8,8,8,15" 121.Content="Overview Required" 122.Grid.Row="7" 123.Grid.ColumnSpan="2" 124.IsChecked="{Binding activeJob.NeedsOverview, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 125. 126.<CheckBox x:Name="xJobActiveCB" Margin="8,8,8,15" 127.Content="Job is Active" 128.Grid.Column="2" 129.Grid.Row="7" 130.IsChecked="{Binding activeJob.IsActive, Mode=TwoWay, NotifyOnValidationError=True, ValidatesOnExceptions=True}"/> 131. 132.<!-- Buttons --> 133. 134.<Button x:Name="xAddEditButton" Margin="8,8,0,10" 135.Content="{Binding AddEditButtonString}" 136.cal:Click.Command="{Binding AddEditCommand}" 137.Grid.Column="2" 138.Grid.Row="8" 139.HorizontalAlignment="Left" 140.Width="125" 141.telerik:StyleManager.Theme="Windows7" /> 142. 143.<Button x:Name="xCancelButton" HorizontalAlignment="Right" 144.Content="Cancel" 145.cal:Click.Command="{Binding CancelCommand}" 146.Margin="0,8,8,10" 147.Width="125" 148.Grid.Column="2" 149.Grid.Row="8" 150.telerik:StyleManager.Theme="Windows7" /> 151.</Grid> 152.</Grid> The 'validationHelper:ValidationScope' line may seem odd. This is a handy little trick for catching current and would-be validation errors when working in this whole setup. This all comes from an approach found on theJoy Of Code blog, although it looks like the story for this will be changing slightly with new advances in SL4/WCF RIA Services, so this section can definitely get an overhaul a little down the road. The code is the fun part of all this, so let us see what's happening under the hood. Viewmodel for the AddEditJobView We are going to see some of the same things happening here, so I'll skip over the repeat info and get right to the good stuff: 001.public class AddEditJobViewModel : ViewModelBase 002.{ 003.private readonly IEventAggregator eventAggregator; 004.private readonly IRegionManager regionManager; 005. 006.public RecruitingContext context; 007. 008.private JobPosting _activeJob; 009.public JobPosting activeJob 010.{ 011.get { return _activeJob; } 012.set 013.{ 014.if (_activeJob != value) 015.{ 016._activeJob = value; 017.NotifyChanged("activeJob"); 018.} 019.} 020.} 021. 022.public bool isNewJob; 023. 024.private string _addEditString; 025.public string AddEditString 026.{ 027.get { return _addEditString; } 028.set 029.{ 030.if (_addEditString != value) 031.{ 032._addEditString = value; 033.NotifyChanged("AddEditString"); 034.} 035.} 036.} 037. 038.private string _addEditButtonString; 039.public string AddEditButtonString 040.{ 041.get { return _addEditButtonString; } 042.set 043.{ 044.if (_addEditButtonString != value) 045.{ 046._addEditButtonString = value; 047.NotifyChanged("AddEditButtonString"); 048.} 049.} 050.} 051. 052.public SubscriptionToken addJobToken = new SubscriptionToken(); 053.public SubscriptionToken editJobToken = new SubscriptionToken(); 054. 055.public DelegateCommand<object> AddEditCommand { get; set; } 056.public DelegateCommand<object> CancelCommand { get; set; } 057. 058.private ObservableCollection<ValidationError> _errors = new ObservableCollection<ValidationError>(); 059.public ObservableCollection<ValidationError> Errors 060.{ 061.get { return _errors; } 062.} 063. 064.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 065.public ObservableCollection<ValidationResult> ValResults 066.{ 067.get { return this._valResults; } 068.} 069. 070.public AddEditJobViewModel(IEventAggregator eventAgg, IRegionManager regionmanager) 071.{ 072.// set Unity items 073.this.eventAggregator = eventAgg; 074.this.regionManager = regionmanager; 075. 076.context = new RecruitingContext(); 077. 078.AddEditCommand = new DelegateCommand<object>(this.AddEditJobCommand); 079.CancelCommand = new DelegateCommand<object>(this.CancelAddEditCommand); 080. 081.SetSubscriptions(); 082.} 083. 084.#region Subscription Declaration and Events 085. 086.public void SetSubscriptions() 087.{ 088.AddJobEvent addJob = this.eventAggregator.GetEvent<AddJobEvent>(); 089. 090.if (addJobToken != null) 091.addJob.Unsubscribe(addJobToken); 092. 093.addJobToken = addJob.Subscribe(this.AddJobEventHandler); 094. 095.EditJobEvent editJob = this.eventAggregator.GetEvent<EditJobEvent>(); 096. 097.if (editJobToken != null) 098.editJob.Unsubscribe(editJobToken); 099. 100.editJobToken = editJob.Subscribe(this.EditJobEventHandler); 101.} 102. 103.public void AddJobEventHandler(bool isNew) 104.{ 105.this.activeJob = null; 106.this.activeJob = new JobPosting(); 107.this.activeJob.IsActive = true; // We assume that we want a new job to go up immediately 108.this.isNewJob = true; 109.this.AddEditString = "Add New Job Posting"; 110.this.AddEditButtonString = "Add Job"; 111. 112.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 113.} 114. 115.public void EditJobEventHandler(JobPosting editJob) 116.{ 117.this.activeJob = null; 118.this.activeJob = editJob; 119.this.isNewJob = false; 120.this.AddEditString = "Edit Job Posting"; 121.this.AddEditButtonString = "Edit Job"; 122. 123.MakeMeActive(this.regionManager, "MainRegion", "AddEditJobView"); 124.} 125. 126.#endregion 127. 128.#region DelegateCommands from View 129. 130.public void AddEditJobCommand(object obj) 131.{ 132.if (this.Errors.Count > 0) 133.{ 134.List<string> errorMessages = new List<string>(); 135. 136.foreach (var valR in this.Errors) 137.{ 138.errorMessages.Add(valR.Exception.Message); 139.} 140. 141.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 142. 143.} 144.else if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 145.{ 146.List<string> errorMessages = new List<string>(); 147. 148.foreach (var valR in this._valResults) 149.{ 150.errorMessages.Add(valR.ErrorMessage); 151.} 152. 153.this._valResults.Clear(); 154. 155.this.eventAggregator.GetEvent<DisplayValidationErrorsEvent>().Publish(errorMessages); 156.} 157.else 158.{ 159.if (this.isNewJob) 160.{ 161.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(this.activeJob); 162.} 163.else 164.{ 165.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(true); 166.} 167.} 168.} 169. 170.public void CancelAddEditCommand(object obj) 171.{ 172.if (this.isNewJob) 173.{ 174.this.eventAggregator.GetEvent<AddJobCompleteEvent>().Publish(null); 175.} 176.else 177.{ 178.this.eventAggregator.GetEvent<EditJobCompleteEvent>().Publish(false); 179.} 180.} 181. 182.#endregion 183.} 184.} We start seeing something new on line 103- the AddJobEventHandler will create a new job and set that to the activeJob item on the ViewModel. When this is all set, the view calls that familiar MakeMeActive method to activate itself. I made a bit of a management call on making views self-activate like this, but I figured it works for one reason. As I create this application, views may not exist that I have in mind, so after a view receives its 'ping' from being subscribed to an event, it prepares whatever it needs to do and then goes active. This way if I don't have 'edit' hooked up, I can click as the day is long on the main view and won't get lost in an empty region. Total personal preference here. :) Everything else should again be pretty straightforward, although I do a bit of validation checking in the AddEditJobCommand, which can either fire off an event back to the main view/viewmodel if everything is a success or sent a list of errors to our notification module, which pops open a RadWindow with the alerts if any exist. As a bonus side note, here's what my WCF RIA Services metadata looks like for handling all of the validation: private JobPostingMetadata() { } [StringLength(2500, ErrorMessage = "Description should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage = "Description is required.")] public string Description; [Required(ErrorMessage="Active Status is Required")] public bool IsActive; [StringLength(100, ErrorMessage = "Posting title must be more than 3 but less than 100 characters.", MinimumLength = 3)] [Required(ErrorMessage = "Job Title is required.")] public bool JobTitle; [Required] public string Location; public bool NeedsCV; public bool NeedsOverview; public bool NeedsResume; public int PostingID; [Required(ErrorMessage="Qualifications are required.")] [StringLength(2500, ErrorMessage="Qualifications should be more than one and less than 2500 characters.", MinimumLength=1)] public string Qualifications; [StringLength(2500, ErrorMessage = "Requirements should be more than one and less than 2500 characters.", MinimumLength = 1)] [Required(ErrorMessage="Requirements are required.")] public string Requirements;   The RecruitCB Alternative See all that Xaml I pasted above? Those are now two pieces sitting in the JobsView.xaml file now. The only real difference is that the xEditGrid now sits in the same place as xJobsGrid, with visibility swapping out between the two for a quick switch. I also took out all the cal: and command: command references and replaced Button events with clicks and the Grid selection command replaced with a SelectedItemChanged event. Also, at the bottom of the xEditGrid after the last button, I add a ValidationSummary (with Visibility=Collapsed) to catch any errors that are popping up. Simple as can be, and leads to this being the single code-behind file: 001.public partial class JobsView : UserControl 002.{ 003.public RecruitingContext context; 004.public JobPosting activeJob; 005.public bool isNew; 006.private ObservableCollection<ValidationResult> _valResults = new ObservableCollection<ValidationResult>(); 007.public ObservableCollection<ValidationResult> ValResults 008.{ 009.get { return this._valResults; } 010.} 011.public JobsView() 012.{ 013.InitializeComponent(); 014.this.Loaded += new RoutedEventHandler(JobsView_Loaded); 015.} 016.void JobsView_Loaded(object sender, RoutedEventArgs e) 017.{ 018.context = new RecruitingContext(); 019.xJobsGrid.ItemsSource = context.JobPostings; 020.context.Load(context.GetJobPostingsQuery()); 021.} 022.private void xAddRecordButton_Click(object sender, RoutedEventArgs e) 023.{ 024.activeJob = new JobPosting(); 025.isNew = true; 026.xAddEditTitle.Text = "Add a Job Posting"; 027.xAddEditButton.Content = "Add"; 028.xEditGrid.DataContext = activeJob; 029.HideJobsGrid(); 030.} 031.private void xEditRecordButton_Click(object sender, RoutedEventArgs e) 032.{ 033.activeJob = xJobsGrid.SelectedItem as JobPosting; 034.isNew = false; 035.xAddEditTitle.Text = "Edit a Job Posting"; 036.xAddEditButton.Content = "Edit"; 037.xEditGrid.DataContext = activeJob; 038.HideJobsGrid(); 039.} 040.private void xAddEditButton_Click(object sender, RoutedEventArgs e) 041.{ 042.if (!Validator.TryValidateObject(this.activeJob, new ValidationContext(this.activeJob, null, null), _valResults, true)) 043.{ 044.List<string> errorMessages = new List<string>(); 045.foreach (var valR in this._valResults) 046.{ 047.errorMessages.Add(valR.ErrorMessage); 048.} 049.this._valResults.Clear(); 050.ShowErrors(errorMessages); 051.} 052.else if (xSummary.Errors.Count > 0) 053.{ 054.List<string> errorMessages = new List<string>(); 055.foreach (var err in xSummary.Errors) 056.{ 057.errorMessages.Add(err.Message); 058.} 059.ShowErrors(errorMessages); 060.} 061.else 062.{ 063.if (this.isNew) 064.{ 065.context.JobPostings.Add(activeJob); 066.context.SubmitChanges((s) => 067.{ 068.ActionHistory thisAction = new ActionHistory(); 069.thisAction.PostingID = activeJob.PostingID; 070.thisAction.Description = String.Format("Job '{0}' has been edited by {1}", activeJob.JobTitle, "default user"); 071.thisAction.TimeStamp = DateTime.Now; 072.context.ActionHistories.Add(thisAction); 073.context.SubmitChanges(); 074.}, null); 075.} 076.else 077.{ 078.context.SubmitChanges((s) => 079.{ 080.ActionHistory thisAction = new ActionHistory(); 081.thisAction.PostingID = activeJob.PostingID; 082.thisAction.Description = String.Format("Job '{0}' has been added by {1}", activeJob.JobTitle, "default user"); 083.thisAction.TimeStamp = DateTime.Now; 084.context.ActionHistories.Add(thisAction); 085.context.SubmitChanges(); 086.}, null); 087.} 088.ShowJobsGrid(); 089.} 090.} 091.private void xCancelButton_Click(object sender, RoutedEventArgs e) 092.{ 093.ShowJobsGrid(); 094.} 095.private void ShowJobsGrid() 096.{ 097.xAddEditRecordButtonPanel.Visibility = Visibility.Visible; 098.xEditGrid.Visibility = Visibility.Collapsed; 099.xJobsGrid.Visibility = Visibility.Visible; 100.} 101.private void HideJobsGrid() 102.{ 103.xAddEditRecordButtonPanel.Visibility = Visibility.Collapsed; 104.xJobsGrid.Visibility = Visibility.Collapsed; 105.xEditGrid.Visibility = Visibility.Visible; 106.} 107.private void ShowErrors(List<string> errorList) 108.{ 109.string nm = "Errors received: \n"; 110.foreach (string anerror in errorList) 111.nm += anerror + "\n"; 112.RadWindow.Alert(nm); 113.} 114.} The first 39 lines should be pretty familiar, not doing anything too unorthodox to get this up and running. Once we hit the xAddEditButton_Click on line 40, we're still doing pretty much the same things except instead of checking the ValidationHelper errors, we both run a check on the current activeJob object as well as check the ValidationSummary errors list. Once that is set, we again use the callback of context.SubmitChanges (lines 68 and 78) to create an ActionHistory which we will use to track these items down the line. That's all? Essentially... yes. If you look back through this post, most of the code and adventures we have taken were just to get things working in the MVVM/Prism setup. Since I have the whole 'module' self-contained in a single JobView+code-behind setup, I don't have to worry about things like sending events off into space for someone to pick up, communicating through an Infrastructure project, or even re-inventing events to be used with attached behaviors. Everything just kinda works, and again with much less code. Here's a picture of the MVVM and Code-behind versions on the Jobs and AddEdit views, but since the functionality is the same in both apps you still cannot tell them apart (for two-strike): Looking ahead, the Applicants module is effectively the same thing as the Jobs module, so most of the code is being cut-and-pasted back and forth with minor tweaks here and there. So that one is being taken care of by me behind the scenes. Next time, we get into a new world of fun- the interview scheduling module, which will pull from available jobs and applicants for each interview being scheduled, tying everything together with RadScheduler to the rescue. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

  Read the article

• Internet Explorer 8 Standards Mode Results In Broken Blank Page

  - by Agent_9191

  I'm running into a weird issue that I'm struggling to figure out what's causing the page to break. I have an internal website that's still under development (thus no link to the page) that works great in Firefox and Internet Explorer 8 in IE 7 Standards mode. But when I force it to IE 8 Standards mode the page will only display the title text in the browser tab and an otherwise completely blank page. It seems so broken that the blank page doesn't even have a context menu. The page generally looks like this: <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta content="IE=8" http-equiv="X-UA-Compatible" /> <title>Page Title</title> <link rel="shortcut icon" href="/Images/favicon.ico" type="image/x-icon" /> <link href="/Style/main.less" rel="stylesheet" type="text/css" /> </head> <body> ... </body> </html> You may notice the .less extension for the stylesheet. This is an ASP.NET MVC application and I'm making use of DotLess. I have the HttpHandler hooked up for it in the web.config. Of course there's some additional info on the page, but (in theory) it shouldn't be causing this issue. I've run the CSS and the HTML through the W3C validators and both have come back as completely valid. I'm trying the arduous task of removing/re-adding elements until it displays, but any insight into what could cause this would help. EDIT: it appears to be something related to the DotLess stylesheet. The resulting CSS is valid according to the W3C CSS validator. EDIT 2: Digging further, and making use of IE's Developer Tools to control the styles, it appears that IE is reading a single statement twice even though it only occurs once in the output. Here's the output of the Less file: a, abbr, acronym, address, applet, b, big, caption, center, cite, code, dd, dfn, div, dl, dt, em, fieldset, font, form, html, i, iframe, img, kbd, label, legend, li, object, pre, s, samp, small, span, strike, strong, sub, sup, tbody, td, tfoot, th, thead, tr, tt, u, var { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; } blockquote, q { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; quotes: none; } body { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; line-height: 1; width: 100%; background: #efebde; min-width: 600px; } del { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; text-decoration: line-through; } h1 { border: 0; outline: 0; vertical-align: baseline; background: transparent; font-size: 2em; margin: .8em 0 .2em 0; padding: 0; } h2 { border: 0; outline: 0; vertical-align: baseline; background: transparent; font-size: 1.8em; margin: .8em 0 .2em 0; padding: 0; } h3 { border: 0; outline: 0; vertical-align: baseline; background: transparent; font-size: 1.6em; margin: .8em 0 .2em 0; padding: 0; } h4 { margin: 0; padding: 0; border: 0; outline: 0; vertical-align: baseline; background: transparent; font-size: 1.4em; } h5 { margin: 0; padding: 0; border: 0; outline: 0; vertical-align: baseline; background: transparent; font-size: 1.2em; } h6 { margin: 0; padding: 0; border: 0; outline: 0; vertical-align: baseline; background: transparent; font-size: 1em; } ins { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; text-decoration: none; } ol, ul { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; list-style: none; } p { border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; margin: .4em 0 .8em 0; padding: 0; } table { margin: 0; padding: 0; border: 0; outline: 0; font-size: 100%; vertical-align: baseline; background: transparent; border-collapse: collapse; border-spacing: 0; } blockquote:before, blockquote:after, q:before, q:after { content: none; } :focus { outline: 0; } .bold { font-weight: bold; } .systemFont { font-family: Arial; } .labelled { font-style: italic; } .groovedBorder { border-color: #adaa9c; border-style: groove; border-width: medium; } #header, #footer { clear: both; float: left; width: 100%; } #header p, #header h1, #header h2 { padding: .4em 15px 0 15px; margin: 0; } #header ul { clear: left; float: left; width: 100%; list-style: none; margin: 10px 0 0 0; padding: 0; } #header ul li { display: inline; list-style: none; margin: 0; padding: 0; } #header ul li a { background: #eeeeee; display: block; float: left; left: 15px; line-height: 1.3em; margin: 0 0 0 1px; padding: 3px 10px; position: relative; text-align: center; text-decoration: none; } #header ul li a span { display: block; } #header ul li a:hover { background: #336699; } #header ul li a.active, #header ul li a.active:hover { background: black; font-weight: bold; } #header #logindisplay { float: right; padding-top: .5em; padding-bottom: .5em; padding-right: 1em; padding-left: 1em; } #title h1 { font-family: Arial; font-style: italic; font-size: 175%; text-align: center; margin-top: 1%; } .col1 { font-family: Arial; border-color: #adaa9c; border-style: groove; border-width: medium; min-height: 350px; float: left; overflow: hidden; position: relative; padding-top: 0; padding-bottom: 1em; padding-left: 0; padding-right: 0; } .col1 div.logo { text-align: center; } .col3 { font-family: Arial; border-color: #adaa9c; border-style: groove; border-width: medium; float: left; overflow: hidden; position: relative; } #layoutdims { clear: both; background: #eeeeee; margin: 0; padding: 6px 15px !important; text-align: right; } #company { padding-left: 10px; padding-top: 10px; margin: 0; } #company span { display: block; padding-left: 1em; } #version { padding-right: 1em; padding-top: 1em; text-align: center; } #menu li { padding: 6px; border-color: #adaa9c; border-style: groove; border-width: medium; min-width: 108px; } #menu li a.ciApp { text-decoration: none; font-size: 112.5%; font-weight: bold; font-family: Arial; color: black; } #menu li a.ciApp span { vertical-align: top; } .welcomemessage { font-size: 60.95%; } .newFeatures { overflow-y: scroll; max-height: 300px; } #newsfeed div .newsLabel { color: red; font-size: 60.95%; font-style: italic; } /************************************************************************************** This statement appears twice in Developer Tools. Disabling one disables both. Disabling it also causes the page to render. Turning it on and the page disappears again **************************************************************************************/ #newsfeed div .newFeatures { margin-left: 1em; margin-right: 1em; font-size: 60.95%; } /************************************************************************************** **************************************************************************************/ .colmask { clear: both; float: left; position: relative; overflow: hidden; width: 100%; } .colright, .colmid, .colleft { float: left; position: relative; width: 100%; } .col2 { float: left; overflow: hidden; position: relative; padding-top: 0; padding-bottom: 1em; padding-left: 0; padding-right: 0; } .threecol .colmid { right: 33%; } .threecol .colleft { right: 34%; } .threecol .col1 { width: 33%; left: 100%; } .threecol .col2 { width: 32%; left: 34%; } .threecol .col3 { width: 32%; left: 68.5%; } Notice the #newsfeed div .newFeatures identifier near the end. I don't know what's causing that as it's only appearing once in the output stream. Here's an image of it too: EDIT 3: It appears that even though it duplicates that particular selector, if I change the font-size to a whole number like 61% instead of the current 60.95% (that specific to defaultly match the existing desktop app as closely as possible) it works fine. So something specific to IE duplicating that selector block and the font-size being a percentage specific to two decimal places appears to kill IE8 Standards mode completely.

  Read the article

• UIImagePickerController, UIImage, Memory and More!

  - by Itay

  I've noticed that there are many questions about how to handle UIImage objects, especially in conjunction with UIImagePickerController and then displaying it in a view (usually a UIImageView). Here is a collection of common questions and their answers. Feel free to edit and add your own. I obviously learnt all this information from somewhere too. Various forum posts, StackOverflow answers and my own experimenting brought me to all these solutions. Credit goes to those who posted some sample code that I've since used and modified. I don't remember who you all are - but hats off to you! How Do I Select An Image From the User's Images or From the Camera? You use UIImagePickerController. The documentation for the class gives a decent overview of how one would use it, and can be found here. Basically, you create an instance of the class, which is a modal view controller, display it, and set yourself (or some class) to be the delegate. Then you'll get notified when a user selects some form of media (movie or image in 3.0 on the 3GS), and you can do whatever you want. My Delegate Was Called - How Do I Get The Media? The delegate method signature is the following: - (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info; You should put a breakpoint in the debugger to see what's in the dictionary, but you use that to extract the media. For example: UIImage* image = [info objectForKey:UIImagePickerControllerOriginalImage]; There are other keys that work as well, all in the documentation. OK, I Got The Image, But It Doesn't Have Any Geolocation Data. What gives? Unfortunately, Apple decided that we're not worthy of this information. When they load the data into the UIImage, they strip it of all the EXIF/Geolocation data. Can I Get To The Original File Representing This Image on the Disk? Nope. For security purposes, you only get the UIImage. How Can I Look At The Underlying Pixels of the UIImage? Since the UIImage is immutable, you can't look at the direct pixels. However, you can make a copy. The code to this looks something like this: UIImage* image = ...; // An image NSData* pixelData = (NSData*) CGDataProviderCopyData(CGImageGetDataProvider(image.CGImage)); unsigned char* pixelBytes = (unsigned char *)[pixelData bytes]; // Take away the red pixel, assuming 32-bit RGBA for(int i = 0; i < [pixelData length]; i += 4) { pixelBytes[i] = 0; // red pixelBytes[i+1] = pixelBytes[i+1]; // green pixelBytes[i+2] = pixelBytes[i+2]; // blue pixelBytes[i+3] = pixelBytes[i+3]; // alpha } However, note that CGDataProviderCopyData provides you with an "immutable" reference to the data - meaning you can't change it (and you may get a BAD_ACCESS error if you do). Look at the next question if you want to see how you can modify the pixels. How Do I Modify The Pixels of the UIImage? The UIImage is immutable, meaning you can't change it. Apple posted a great article on how to get a copy of the pixels and modify them, and rather than copy and paste it here, you should just go read the article. Once you have the bitmap context as they mention in the article, you can do something similar to this to get a new UIImage with the modified pixels: CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; Do remember to release your references though, otherwise you're going to be leaking quite a bit of memory. After I Select 3 Images From The Camera, I Run Out Of Memory. Help! You have to remember that even though on disk these images take up only a few hundred kilobytes at most, that's because they're compressed as a PNG or JPG. When they are loaded into the UIImage, they become uncompressed. A quick over-the-envelope calculation would be: width x height x 4 = bytes in memory That's assuming 32-bit pixels. If you have 16-bit pixels (some JPGs are stored as RGBA-5551), then you'd replace the 4 with a 2. Now, images taken with the camera are 1600 x 1200 pixels, so let's do the math: 1600 x 1200 x 4 = 7,680,000 bytes = ~8 MB 8 MB is a lot, especially when you have a limit of around 24 MB for your application. That's why you run out of memory. OK, I Understand Why I Have No Memory. What Do I Do? There is never any reason to display images at their full resolution. The iPhone has a screen of 480 x 320 pixels, so you're just wasting space. If you find yourself in this situation, ask yourself the following question: Do I need the full resolution image? If the answer is yes, then you should save it to disk for later use. If the answer is no, then read the next part. Once you've decided what to do with the full-resolution image, then you need to create a smaller image to use for displaying. Many times you might even want several sizes for your image: a thumbnail, a full-size one for displaying, and the original full-resolution image. OK, I'm Hooked. How Do I Resize the Image? Unfortunately, there is no defined way how to resize an image. Also, it's important to note that when you resize it, you'll get a new image - you're not modifying the old one. There are a couple of methods to do the resizing. I'll present them both here, and explain the pros and cons of each. Method 1: Using UIKit + (UIImage*)imageWithImage:(UIImage*)image scaledToSize:(CGSize)newSize; { // Create a graphics image context UIGraphicsBeginImageContext(newSize); // Tell the old image to draw in this new context, with the desired // new size [image drawInRect:CGRectMake(0,0,newSize.width,newSize.height)]; // Get the new image from the context UIImage* newImage = UIGraphicsGetImageFromCurrentImageContext(); // End the context UIGraphicsEndImageContext(); // Return the new image. return newImage; } This method is very simple, and works great. It will also deal with the UIImageOrientation for you, meaning that you don't have to care whether the camera was sideways when the picture was taken. However, this method is not thread safe, and since thumbnailing is a relatively expensive operation (approximately ~2.5s on a 3G for a 1600 x 1200 pixel image), this is very much an operation you may want to do in the background, on a separate thread. Method 2: Using CoreGraphics + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSize:(CGSize)newSize; { CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } if (sourceImage.imageOrientation == UIImageOrientationLeft) { CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(0, 0, targetWidth, targetHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The benefit of this method is that it is thread-safe, plus it takes care of all the small things (using correct color space and bitmap info, dealing with image orientation) that the UIKit version does. How Do I Resize and Maintain Aspect Ratio (like the AspectFill option)? It is very similar to the method above, and it looks like this: + (UIImage*)imageWithImage:(UIImage*)sourceImage scaledToSizeWithSameAspectRatio:(CGSize)targetSize; { CGSize imageSize = sourceImage.size; CGFloat width = imageSize.width; CGFloat height = imageSize.height; CGFloat targetWidth = targetSize.width; CGFloat targetHeight = targetSize.height; CGFloat scaleFactor = 0.0; CGFloat scaledWidth = targetWidth; CGFloat scaledHeight = targetHeight; CGPoint thumbnailPoint = CGPointMake(0.0,0.0); if (CGSizeEqualToSize(imageSize, targetSize) == NO) { CGFloat widthFactor = targetWidth / width; CGFloat heightFactor = targetHeight / height; if (widthFactor > heightFactor) { scaleFactor = widthFactor; // scale to fit height } else { scaleFactor = heightFactor; // scale to fit width } scaledWidth = width * scaleFactor; scaledHeight = height * scaleFactor; // center the image if (widthFactor > heightFactor) { thumbnailPoint.y = (targetHeight - scaledHeight) * 0.5; } else if (widthFactor < heightFactor) { thumbnailPoint.x = (targetWidth - scaledWidth) * 0.5; } } CGImageRef imageRef = [sourceImage CGImage]; CGBitmapInfo bitmapInfo = CGImageGetBitmapInfo(imageRef); CGColorSpaceRef colorSpaceInfo = CGImageGetColorSpace(imageRef); if (bitmapInfo == kCGImageAlphaNone) { bitmapInfo = kCGImageAlphaNoneSkipLast; } CGContextRef bitmap; if (sourceImage.imageOrientation == UIImageOrientationUp || sourceImage.imageOrientation == UIImageOrientationDown) { bitmap = CGBitmapContextCreate(NULL, targetWidth, targetHeight, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } else { bitmap = CGBitmapContextCreate(NULL, targetHeight, targetWidth, CGImageGetBitsPerComponent(imageRef), CGImageGetBytesPerRow(imageRef), colorSpaceInfo, bitmapInfo); } // In the right or left cases, we need to switch scaledWidth and scaledHeight, // and also the thumbnail point if (sourceImage.imageOrientation == UIImageOrientationLeft) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(90)); CGContextTranslateCTM (bitmap, 0, -targetHeight); } else if (sourceImage.imageOrientation == UIImageOrientationRight) { thumbnailPoint = CGPointMake(thumbnailPoint.y, thumbnailPoint.x); CGFloat oldScaledWidth = scaledWidth; scaledWidth = scaledHeight; scaledHeight = oldScaledWidth; CGContextRotateCTM (bitmap, radians(-90)); CGContextTranslateCTM (bitmap, -targetWidth, 0); } else if (sourceImage.imageOrientation == UIImageOrientationUp) { // NOTHING } else if (sourceImage.imageOrientation == UIImageOrientationDown) { CGContextTranslateCTM (bitmap, targetWidth, targetHeight); CGContextRotateCTM (bitmap, radians(-180.)); } CGContextDrawImage(bitmap, CGRectMake(thumbnailPoint.x, thumbnailPoint.y, scaledWidth, scaledHeight), imageRef); CGImageRef ref = CGBitmapContextCreateImage(bitmap); UIImage* newImage = [UIImage imageWithCGImage:ref]; CGContextRelease(bitmap); CGImageRelease(ref); return newImage; } The method we employ here is to create a bitmap with the desired size, but draw an image that is actually larger, thus maintaining the aspect ratio. So We've Got Our Scaled Images - How Do I Save Them To Disk? This is pretty simple. Remember that we want to save a compressed version to disk, and not the uncompressed pixels. Apple provides two functions that help us with this (documentation is here): NSData* UIImagePNGRepresentation(UIImage *image); NSData* UIImageJPEGRepresentation (UIImage *image, CGFloat compressionQuality); And if you want to use them, you'd do something like: UIImage* myThumbnail = ...; // Get some image NSData* imageData = UIImagePNGRepresentation(myThumbnail); Now we're ready to save it to disk, which is the final step (say into the documents directory): // Give a name to the file NSString* imageName = @"MyImage.png"; // Now, we have to find the documents directory so we can save it // Note that you might want to save it elsewhere, like the cache directory, // or something similar. NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES); NSString* documentsDirectory = [paths objectAtIndex:0]; // Now we get the full path to the file NSString* fullPathToFile = [documentsDirectory stringByAppendingPathComponent:imageName]; // and then we write it out [imageData writeToFile:fullPathToFile atomically:NO]; You would repeat this for every version of the image you have. How Do I Load These Images Back Into Memory? Just look at the various UIImage initialization methods, such as +imageWithContentsOfFile: in the Apple documentation.

  Read the article

< Previous Page | 17 18 19 20 21