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• Book Review: Oracle ADF Real World Developer’s Guide

  - by Frank Nimphius

  Recently PACKT Publishing published "Oracle ADF Real World Developer’s Guide" by Jobinesh Purushothaman, a product manager in our team. Though already the sixth book dedicated to Oracle ADF, it has a lot of great information in it that none of the previous books covered, making it a safe buy even for those who own the other books published by Oracle Press (McGrwHill) and PACKT Publishing. More than the half of the "Oracle ADF Real World Developer’s Guide" book is dedicated to Oracle ADF Business Components in a depth and clarity that allows you to feel the expertise that Jobinesh gained in this area. If you enjoy Jobinesh blog (http://jobinesh.blogspot.co.uk/) about Oracle ADF, then, no matter what expert you are in Oracle ADF, this book makes you happy as it provides you with detail information you always wished to have. If you are new to Oracle ADF, then this book alone doesn't get you flying, but, if you have some Java background, accelerates your learning big, big, big times. Chapter 1 is an introduction to Oracle ADF and not only explains the layers but also how it compares to plain Java EE solutions (page 13). If you are new to Oracle JDeveloper and ADF, then at the end of this chapter you know how to start JDeveloper and begin your ADF development Chapter 2 starts with what Jobinesh really is good at: ADF Business Components. In this chapter you learn about the architecture ingredients of ADF Business Components: View Objects, View Links, Associations, Entities, Row Sets, Query Collections and Application Modules. This chapter also provides a introduction to ADFBC SDO services, as well as sequence diagrams for what happens when you execute queries or commit updates. Chapter 3 is dedicated to entity objects and  is one of many chapters in this book you will enjoy and never want to miss. Jobinesh explains the artifacts that make up an entity object, how to work with entities and resource bundles, and many advanced topics, including inheritance, change history tracking, custom properties, validation and cursor handling.  Chapter 4 - you guessed it - is all about View objects. Comparable to entities, you learn about the XM files and classes that make a view object, as well as how to define and work with queries. List-of-values, inheritance, polymorphism, bind variables and data filtering are interesting - and important topics that follow. Again the chapter provides helpful sequence diagrams for you to understand what happens internally within a view object. Chapter 5 focuses on advanced view object and entity object topics, like lifecycle callback methods and when you want to override them. This chapter is a good digest of Jobinesh's blog entries (which most ADF developers have in their bookmark list). Really worth reading ! Chapter 6 then is bout Application Modules. Beside of what application modules are, this chapter covers important topics like properties, passivation, activation, application module pooling, how and where to write custom logic. In addition you learn about the AM lifecycle and request sequence. Chapter 7 is about the ADF binding layer. If you are new to Oracle ADF and got lost in the more advanced ADF Business Components chapters, then this chapter is where you get back into the game. In very easy terms, Jobinesh explains what the ADF binding is, how it fits into the JSF request lifecycle and what are the metadata file involved. Chapter 8 then goes into building data bound web user interfaces. In this chapter you get the basics of JavaServer Faces (e.g. managed beans) and learn about the interaction between the JSF UI and the ADF binding layer. Later this chapter provides advanced solutions for working with tree components and list of values. Chapter 9 introduces bounded task flows and ADF controller. This is a chapter you want to read if you are new to ADF of have started. Experts don't find anything new here, which doesn't mean that it is not worth reading it (I for example, enjoyed the controller talk very much) Chapter 10 is an advanced coverage of bounded task flow and talks about contextual events  Chapter 11 is another highlight and explains error handling, trains, transactions and more. I can only recommend you read this chapter. I am aware of many documents that cover exception handling in Oracle ADF (and my Oracle Magazine article for January/February 2013 does the same), but none that covers it in such a great depth. Chapter 12 covers ADF best practices, which is a great round-up of all the tips provided in this book (without Jobinesh to repeat himself). Its all cool stuff that helps you with your ADF projects. In summary, "Oracle ADF Real World Developer’s Guide" by Jobinesh Purushothaman is a great book and addition for all Oracle ADF developers and those who want to become one. Frank

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• Silverlight Chat WrapPanel Crash / Bug

  - by Matt

  I've been given the task to create a simple Silverlight chat box for two people. My control must adhere to the following requirements Scrollable Text must wrap if it's too long When a new item / message is added it must scroll that item into view Now I've successfully made a usercontrol to meet these requirements, but I've run into a possible bug / crash that I can't for the life of me fix. I'm looking for either a fix to the bug, or a different approach to creating a scrollable chat control. Here's the code I've been using. We'll start with my XAML for the chat window <ListBox x:Name="lbChatHistory" Grid.Row="0" Grid.Column="0" Grid.ColumnSpan="2" ScrollViewer.VerticalScrollBarVisibility="Visible" ScrollViewer.HorizontalScrollBarVisibility="Disabled" > <ListBox.ItemTemplate> <DataTemplate> <Grid Background="Beige"> <Grid.ColumnDefinitions> <ColumnDefinition Width="70"></ColumnDefinition> <ColumnDefinition Width="Auto"></ColumnDefinition> </Grid.ColumnDefinitions> <TextBlock x:Name="lblPlayer" Foreground="{Binding ForeColor}" Text="{Binding Player}" Grid.Column="0"></TextBlock> <ContentPresenter Grid.Column="1" Width="200" Content="{Binding Message}" /> </Grid> </DataTemplate> </ListBox.ItemTemplate> </ListBox> The idea is to add a new Item to the listbox. The Item (as layed out in the XAML) is a simple 2 column grid. One column for the username, and one column for the message. Now the "items" that I add to the ListBox is a custom class. It has three properties (Player, ForeColor, and Message) that I using binding on within my XAML Player is a string of the current user to display. ForeColor is just a foreground color preference. It helps distinguish the difference between messages. Message is a WrapPanel. I programmatically break the supplied string on the white space for each word. Then for each word, I add a new TextBlock element to the WrapPanel Here is the custom class. public class ChatMessage :DependencyObject, INotifyPropertyChanged { public event PropertyChangedEventHandler PropertyChanged; public static DependencyProperty PlayerProperty = DependencyProperty.Register( "Player", typeof( string ), typeof( ChatMessage ), new PropertyMetadata( new PropertyChangedCallback( OnPlayerPropertyChanged ) ) ); public static DependencyProperty MessageProperty = DependencyProperty.Register( "Message", typeof( WrapPanel ), typeof( ChatMessage ), new PropertyMetadata( new PropertyChangedCallback( OnMessagePropertyChanged ) ) ); public static DependencyProperty ForeColorProperty = DependencyProperty.Register( "ForeColor", typeof( SolidColorBrush ), typeof( ChatMessage ), new PropertyMetadata( new PropertyChangedCallback( OnForeColorPropertyChanged ) ) ); private static void OnForeColorPropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) { ChatMessage c = d as ChatMessage; c.ForeColor = ( SolidColorBrush ) e.NewValue; } public ChatMessage() { Message = new WrapPanel(); ForeColor = new SolidColorBrush( Colors.White ); } private static void OnMessagePropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) { ChatMessage c = d as ChatMessage; c.Message = ( WrapPanel ) e.NewValue; } private static void OnPlayerPropertyChanged( DependencyObject d, DependencyPropertyChangedEventArgs e ) { ChatMessage c = d as ChatMessage; c.Player = e.NewValue.ToString(); } public SolidColorBrush ForeColor { get { return ( SolidColorBrush ) GetValue( ForeColorProperty ); } set { SetValue( ForeColorProperty, value ); if(PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs( "ForeColor" )); } } public string Player { get { return ( string ) GetValue( PlayerProperty ); } set { SetValue( PlayerProperty, value ); if ( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( "Player" ) ); } } public WrapPanel Message { get { return ( WrapPanel ) GetValue( MessageProperty ); } set { SetValue( MessageProperty, value ); if ( PropertyChanged != null ) PropertyChanged( this, new PropertyChangedEventArgs( "Message" ) ); } } } Lastly I add my items to the ListBox. Here's the simple method. It takes the above ChatMessage class as a parameter public void AddChatItem( ChatMessage msg ) { lbChatHistory.Items.Add( msg ); lbChatHistory.ScrollIntoView( msg ); } Now I've tested this and it all works. The problem I'm getting is when I use the scroll bar. You can scroll down using the side scroll bar or arrow keys, but when you scroll up Silverlight crashes. FireBug returns a ManagedRuntimeError #4004 with a XamlParseException. I'm soo close to having this control work, I can taste it! Any thoughts on what I should do or change? Is there a better approach than the one I've taken? Thanks in advance. UPDATE I've found an alternative solution using a ScrollViewer and an ItemsControl instead of a ListBox control. For the most part it's stable.

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• Silverlight Firestarter Wrap Up and WCF RIA Services Talk Sample Code

  - by dwahlin

  I had a great time attending and speaking at the Silverlight Firestarter event up in Redmond on December 2, 2010. In addition to getting a chance to hang out with a lot of cool people from Microsoft such as Scott Guthrie, John Papa, Tim Heuer, Brian Goldfarb, John Allwright, David Pugmire, Jesse Liberty, Jeff Handley, Yavor Georgiev, Jossef Goldberg, Mike Cook and many others, I also had a chance to chat with a lot of people attending the event and hear about what projects they’re working on which was awesome. If you didn’t get a chance to look through all of the new features coming in Silverlight 5 check out John Papa’s post on the subject. While at the Silverlight Firestarter event I gave a presentation on WCF RIA Services and wanted to get the code posted since several people have asked when it’d be available. The talk can be viewed by clicking the image below. Code from the talk follows as well as additional links. I had a few people ask about the green bracelet on my left hand since it looks like something you’d get from a waterpark. It was used to get us access down a little hall that led backstage and allowed us to go backstage during the event. I thought it looked kind of dorky but it was required to get through security. Sample Code from My WCF RIA Services Talk (To login to the 2 apps use “user” and “P@ssw0rd”. Make sure to do a rebuild of the projects in Visual Studio before running them.) View All Silverlight Firestarter Talks and Scott Guthrie’s Keynote WCF RIA Services SP1 Beta for Silverlight 4 WCF RIA Services Code Samples (including some SP1 samples) Improved binding support in EntitySet and EntityCollection with SP1 (Kyle McClellan’s Blog) Introducing an MVVM-Friendly DomainDataSource: The DomainCollectionView (Kyle McClellan’s Blog) I’ve had the chance to speak at a lot of conferences but never with as many cameras, streaming capabilities, people watching live and overall hype involved. Over 1000 people registered to attend the conference in person at the Microsoft campus and well over 15,000 to watch it through the live stream.  The event started for me on Tuesday afternoon with a flight up to Seattle from Phoenix. My flight was delayed 1 1/2 hours (I seem to be good at booking delayed flights) so I didn’t get up there until almost 8 PM. John Papa did a tech check at 9 PM that night and I was scheduled for 9:30 PM. We basically plugged in my laptop backstage (amazing number of servers, racks and audio devices back there) and made sure everything showed up properly on the projector and the machines recording the presentation. In addition to a dedicated show director, there were at least 5 tech people back stage and at least that many up in the booth running lights, audio, cameras, and other aspects of the show. I wish I would’ve taken a picture of the backstage setup since it was pretty massive – servers all over the place. I definitely gained a new appreciation for how much work goes into these types of events. Here’s what the room looked like right before my tech check– not real exciting at this point. That’s Yavor Georgiev (who spoke on WCF Services at the Firestarter) in the background. We had plenty of monitors to reference during the presentation. Two monitors for slides (right and left side) and a notes monitor. The 4th monitor showed the time and they’d type in notes to us as we talked (such as “You’re over time!” in my case since I went around 4 minutes over :-)). Wednesday morning I went back on campus at Microsoft and watched John Papa film a few Silverlight TV episodes with Dave Campbell and Ryan Plemons.   Next I had the chance to watch the dry run of the keynote with Scott Guthrie and John Papa. We were all blown away by the demos shown since they were even better than expected. Starting at 1 PM on Wednesday I went over to Building 35 and listened to Yavor Georgiev (WCF Services), Jaime Rodriguez (Windows Phone 7), Jesse Liberty (Data Binding) and Jossef Goldberg and Mike Cook (Silverlight Performance) give their different talks and we all shared feedback with each other which was a lot of fun. Jeff Handley from the RIA Services team came afterwards and listened to me give a dry run of my WCF RIA Services talk. He had some great feedback that I really appreciated getting. That night I hung out with John Papa and Ward Bell and listened to John walk through his keynote demos. I also got a sneak peak of the gift given to Dave Campbell for all his work with Silverlight Cream over the years. It’s a poster signed by all of the key people involved with Silverlight: Thursday morning I got up fairly early to get to the event center by 8 AM for speaker pictures. It was nice and quiet at that point although outside the room there was a huge line of people waiting to get in.     At around 8:30 AM everyone was let in and the main room was filled quickly. Two other overflow rooms in the Microsoft conference center (Building 33) were also filled to capacity. At around 9 AM Scott Guthrie kicked off the event and all the excitement started! From there it was all a blur but it was definitely a lot of fun. All of the sessions for the Silverlight Firestarter were recorded and can be watched here (including the keynote). Corey Schuman, John Papa and I also released 11 lab exercises and associated videos to help people get started with Silverlight. Definitely check them out if you’re interested in learning more! Level 100: Getting Started Lab 01 - WinForms and Silverlight Lab 02 - ASP.NET and Silverlight Lab 03 - XAML and Controls Lab 04 - Data Binding Level 200: Ready for More Lab 05 - Migrating Apps to Out-of-Browser Lab 06 - Great UX with Blend Lab 07 - Web Services and Silverlight Lab 08 - Using WCF RIA Services Level 300: Take me Further Lab 09 - Deep Dive into Out-of-Browser Lab 10 - Silverlight Patterns: Using MVVM Lab 11 - Silverlight and Windows Phone 7

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• Using Castle Windsor with FluentValidation In MVC

  - by user332022

  I'm working on getting FluentValidation working with Castle Windsor. I already have a wrapper around Castle Windsor. Here is the code for that: public class ResolveType { private static IWindsorContainer _windsorContainer; public static void Initialize( IWindsorContainer windsorContainer ) { _windsorContainer = windsorContainer; } public static T Of() { return _windsorContainer.Resolve(); } } I am trying to build the FluentValidation factory as is explained at http://www.jeremyskinner.co.uk/2010/02/22/using-fluentvalidation-with-an-ioc-container The article uses StructureMap, but I thought I could adapt it to Castle Windsor like this: public class CastleWindsorValidatorFactory : ValidatorFactoryBase { public override IValidator CreateInstance( Type validatorType) { return ResolveType.Of(); } } Notice, I'm just trying to call into my wrapper so that Windsor can resolve the type reference. The problem is that this doesn't compile. I get 'The type or namespace name 'validatorType' could not be found (are you missing a using directive or an assembly reference?)' How can I make this work?

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• SQLite3's dynamic typing

  - by Bradford Larsen

  SQLite3 uses dynamic typing rather than static typing, in contrast to other flavors of SQL. The SQLite website reads: Most SQL database engines (every SQL database engine other than SQLite, as far as we know) uses static, rigid typing. With static typing, the datatype of a value is determined by its container - the particular column in which the value is stored. SQLite uses a more general dynamic type system. In SQLite, the datatype of a value is associated with the value itself, not with its container. It seems to me that this is exactly what you don't want, as it lets you store, for example, strings in integer columns. The page continues: ...the dynamic typing in SQLite allows it to do things which are not possible in traditional rigidly typed databases. I have two questions: The use case question: What are some examples where sqlite3's dynamic typing is, in fact, beneficial? The historical/design question: What was the motivation for implementing sqlite with dynamic typing?

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• Unable to get the Current User's Token information

  - by Ram

  Hi, I have been trying to get the currently logged-in user's token information using the following code : [DllImport("wtsapi32.dll", CharSet = CharSet.Auto, SetLastError = true)] static extern bool WTSQueryUserToken(int sessionId, out IntPtr tokenHandle); [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)] static extern uint WTSGetActiveConsoleSessionId(); static void Main(string[] args) { try { int sessionID = (int)WTSGetActiveConsoleSessionId(); if (sessionID != -1) { System.IntPtr currentToken = IntPtr.Zero; bool bRet = WTSQueryUserToken(sessionID, out currentToken); Console.WriteLine("bRet : " + bRet.ToString()); } } catch (Exception) { } } The problem is that, bRet is always false and currentToken is always 0. I am getting the sessionid as 1. Could someone tell me what's going wrong here? I want to use this token information to pass it to the CreateProcessAsUser function from a windows service. Thanks, Ram

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• cordova :: XMLHttpRequest :: setRequestHeader does not work with JSONP

  - by Aaron Saunders

  in hello world cordova 2.3.0 app trying to work with ripple added basic BackboneJS code and I get error shown above <script type="text/javascript" src="https://ajax.googleapis.com/ajax/libs/jquery/1.9.0/jquery.min.js"></script> <script type="text/javascript" src="http://static.stackmob.com/js/json2-min.js"></script> <script type="text/javascript" src="http://static.stackmob.com/js/underscore-1.4.3-min.js"></script> <script type="text/javascript" src="http://static.stackmob.com/js/backbone-0.9.10-min.js"></script> I have started google with the proper flags --allow-file-access-from-files

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• ASP.NET Web API and Simple Value Parameters from POSTed data

  - by Rick Strahl

  In testing out various features of Web API I've found a few oddities in the way that the serialization is handled. These are probably not super common but they may throw you for a loop. Here's what I found. Simple Parameters from Xml or JSON Content Web API makes it very easy to create action methods that accept parameters that are automatically parsed from XML or JSON request bodies. For example, you can send a JavaScript JSON object to the server and Web API happily deserializes it for you. This works just fine:public string ReturnAlbumInfo(Album album) { return album.AlbumName + " (" + album.YearReleased.ToString() + ")"; } However, if you have methods that accept simple parameter types like strings, dates, number etc., those methods don't receive their parameters from XML or JSON body by default and you may end up with failures. Take the following two very simple methods:public string ReturnString(string message) { return message; } public HttpResponseMessage ReturnDateTime(DateTime time) { return Request.CreateResponse<DateTime>(HttpStatusCode.OK, time); } The first one accepts a string and if called with a JSON string from the client like this:var client = new HttpClient(); var result = client.PostAsJsonAsync<string>(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, "Hello World").Result; which results in a trace like this: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 13Expect: 100-continueConnection: Keep-Alive "Hello World" produces… wait for it: null. Sending a date in the same fashion:var client = new HttpClient(); var result = client.PostAsJsonAsync<DateTime>(http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime, new DateTime(2012, 1, 1)).Result; results in this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnDateTime HTTP/1.1Content-Type: application/json; charset=utf-8Host: rasxpsContent-Length: 30Expect: 100-continueConnection: Keep-Alive "\/Date(1325412000000-1000)\/" (yes still the ugly MS AJAX date, yuk! This will supposedly change by RTM with Json.net used for client serialization) produces an error response: The parameters dictionary contains a null entry for parameter 'time' of non-nullable type 'System.DateTime' for method 'System.Net.Http.HttpResponseMessage ReturnDateTime(System.DateTime)' in 'AspNetWebApi.Controllers.AlbumApiController'. An optional parameter must be a reference type, a nullable type, or be declared as an optional parameter. Basically any simple parameters are not parsed properly resulting in null being sent to the method. For the string the call doesn't fail, but for the non-nullable date it produces an error because the method can't handle a null value. This behavior is a bit unexpected to say the least, but there's a simple solution to make this work using an explicit [FromBody] attribute:public string ReturnString([FromBody] string message) andpublic HttpResponseMessage ReturnDateTime([FromBody] DateTime time) which explicitly instructs Web API to read the value from the body. UrlEncoded Form Variable Parsing Another similar issue I ran into is with POST Form Variable binding. Web API can retrieve parameters from the QueryString and Route Values but it doesn't explicitly map parameters from POST values either. Taking our same ReturnString function from earlier and posting a message POST variable like this:var formVars = new Dictionary<string,string>(); formVars.Add("message", "Some Value"); var content = new FormUrlEncodedContent(formVars); var client = new HttpClient(); var result = client.PostAsync(http://rasxps/AspNetWebApi/albums/rpc/ReturnString, content).Result; which produces this trace: POST http://rasxps/AspNetWebApi/albums/rpc/ReturnString HTTP/1.1Content-Type: application/x-www-form-urlencodedHost: rasxpsContent-Length: 18Expect: 100-continue message=Some+Value When calling ReturnString:public string ReturnString(string message) { return message; } unfortunately it does not map the message value to the message parameter. This sort of mapping unfortunately is not available in Web API. Web API does support binding to form variables but only as part of model binding, which binds object properties to the POST variables. Sending the same message as in the previous example you can use the following code to pick up POST variable data:public string ReturnMessageModel(MessageModel model) { return model.Message; } public class MessageModel { public string Message { get; set; }} Note that the model is bound and the message form variable is mapped to the Message property as would other variables to properties if there were more. This works but it's not very dynamic. There's no real easy way to retrieve form variables (or query string values for that matter) in Web API's Request object as far as I can discern. Well only if you consider this easy:public string ReturnString() { var formData = Request.Content.ReadAsAsync<FormDataCollection>().Result; return formData.Get("message"); } Oddly FormDataCollection does not allow for indexers to work so you have to use the .Get() method which is rather odd. If you're running under IIS/Cassini you can always resort to the old and trusty HttpContext access for request data:public string ReturnString() { return HttpContext.Current.Request.Form["message"]; } which works fine and is easier. It's kind of a bummer that HttpRequestMessage doesn't expose some sort of raw Request object that has access to dynamic data - given that it's meant to serve as a generic REST/HTTP API that seems like a crucial missing piece. I don't see any way to read query string values either. To me personally HttpContext works, since I don't see myself using self-hosted code much.© Rick Strahl, West Wind Technologies, 2005-2012Posted in Web Api   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); })();

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• PropertyGrid: Merging multiple dynamic properties when editing multiple objects

  - by Andrei Stanescu

  Hi, Let's say I have a class A and a class B. I would like to edit using .NET PropertyGrid multiple instances of A and B simultaneously. The desired behavior would be to have the intersection of properties displayed. If A and B have static (written in the source code) properties everything works fine. Selecting A and B instances will only display the intersection of properties. However, if A and B also have dynamic properties (returned as a PropertyDescriptorCollection through the GetProperties() method) the behavior is wrong. When selecting multiple objects I will only see those static properties and none of the dynamic ones. When I select only one instance I can see all properties (static and dynamic). Anybody any ideas? I couldn't find anything on the internet.

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• Task-It Webinar - Source Code

  Last week I presented a webinar called "Building a real-world application with RadControls for Silverlight 4". For those that didn't get to see the webinar, you can view it here: Building a read-world application with RadControls for Silverlight 4 Since the webinar I've received several requests asking if I could post the source code for the simple application I showed demonstrating some of the techniques used in the development of Task-It, such as MVVM, Commands and Internationalization. This source code is now available for downloadhere. After downloading the source: Extract it to the location of your choice on your hard-drive Open the solution Right-click ModuleProject.Web and selecte 'Set as StartUp Project'. Right-click ProjectTestPage.aspx and selected 'Set as Start Page' Create a database in SQL Server called WebinarProject. Navigate to the Database folder under the WebinarProject directory and run the .sql script against your WebinarProject database. The last two steps are necessary only for the Tasks page to work properly (using WCF RIA Services). Now some notes about each page: Code-behind This is not the way I recommend coding a line-of-business application in Silverlight, but simply wanted to show how the code-behind approach would look. Command This page introduces MVVM and Commands. You'll notice in the XAML that the Command property of theRadMenuItem and the Button are both bound to a SaveCommand. That comes from the view model. If you look in the code- behind of the user control you'll see that an instance of a CommandViewModel is instantiated and set as the DataContext of the UserControl.There is also a listener for the view model's SaveCompleted event. When this is fired, it tells the view (UserControl) to display the MessageBox. Internationalization This sample is similar to the previous one, but instead of using hard-coded strings in the UI, the strings are obtained via binding toview model properties. The view model gets the strings from the .resx files (Strings.resx or Strings.de.resx) under Assets/Resources. If you uncomment the call to ShowGerman() in App.xaml.cs's Application_Startup method and re-run the application, you will see the UI in German. Note that this code, which sets the CurrentCulture and CurrentUICulture on the current thread to "de" (German) is for testing purposes only. RadWindow Once again, very similar to the previous example.The difference is that we are now using a RadWindow to display the 'Saved' message instead of a MessageBox. The advantage here is that we do not have to hold on to a reference to the view model in our code behind so that we can get the 'Saved' message from it. The RadWindow's DataContext is now also bound to the view model, so within its XAML we can bind directly to properties in the view model. Much nicer, and cleaner. One other thing I introduced in this example is the use of spacer Rectangles. Rather than setting a width and/or height on the rectangles for spacing, I am now referencing a style in my ResourceDictionary called StandardSpacerStyle. I like doing this better than using margins or padding because now I have a reusable way to create space between elements, the Rectangle does not show (because I have not set its Fill color), and I can change my spacing throughout the user interface in one place if I'd like. Tasks This page is quite a bit different than the other four. It is a very simple, stripped-down version of the Tasks page in the Task-It application. The Tasks.xaml UserControl has a ContentControl, and the Content of that control is set based on whether we are looking at the list of tasks or editing a task. So it displays one of two child UserControls, which are called List and Details. List has the RadGridView, Details has the form. In the code-behind of the Tasks UserControl I am once again setting its DataContext to a view model class. The nice thing is, whichever child UserControl is being displayed (List or Details) inherits its DataContext from its parent control (Tasks), so I do not have to explicitly set it. The List UserControl simply displays a RadGridView whose ItemsSource is bound to a property in the view model called Tasks, and its SelectedItem property is bound to a property in the view model called SelectedItem. The SelectedItem binding must be TwoWay so that the view is notified when the SelectedItem changes in the view model, and the view model is notified when something changes in the view (like when a user changes the Name and/or DueDate in the form). You'll also notice that the form's TextBox and RadDatePicker are also TwoWay bound to the SelectedItem property in the view model. You can experiment with the binding by removing TwoWay and see how changes in the form do not show up in the RadGridView. So here we have an example of two different views (List and Details) that are both bound to the same view model...and actually, so is the Tasks UserControl, so it is really three views. WCF RIA Services By the way, I am using WCF RIA Services to retrieve data for the RadGridView and save the data when the user clicks the Save button in the form. I created a really simple ADO.NET Entity Data Model in WebinarProject.Web called DataModel.edmx. I also created a simple Domain Data Service called DataService that has methods for retrieving data, inserting, updating and deleting. However I am only using the retrieval and update methods in this sample. Note that I do not currently have any validation in place on the form, as I wanted to keep the sample as simple as possible. Wrap up Technically, I should move the calls to WCF RIA Services out of the view model and put them into a separate layer, but this works for now, and that is a topic for another day! 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.

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• How to access MyProject.MySettings.Default.SomeSetting from xaml?

  - by Shimmy

  I have defined a StringCollection in the Project Settings. I want to use the values in a ComboBox. Is there a way to access it xamly? I tried: <CollectionViewSource Source="{x:Static src:MySettings.Default.MyCollection}" /> <CollectionViewSource x:Key="RoomSections" Source="{x:Static src:MySettings.Default.RoomSections}" /> *src is the xmlns of the project It says: "Type src:MySettings.Default was not found". The thing is that MySettings is a class that offers a Default property which is a thread-safe instance of MySettings, I really want to get the collection from the Default property and not by instantiating a new on. Is there other ways I am not aware of, maybe ObjectDataProvider can access static objects? I thought, maybe I can make in the App.xaml a global resource that return MySettings.Default which is an instance of the MySettings class, and then access all its properties, I will try that out, but I prefer the easy way.

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• Boost Thread Hanging on _endthreadex

  - by FranticPedantic

  I think I am making a simple mistake, but since I noticed there are many boost experts here, I thought I would ask for help. I am trying to use boost threads(1_40) on windows xp. The main program loads a dll, starts the thread like so (note this is not in a class, the static does not mean static to a class but private to the file). static boost::thread network_thread; network_start() { // do network stuff until quit is signaled } DllClass::InitInstance() { network_thread = boost::thread(boost::bind<void>(network_start)); } DllClass::ExitInstance() { //signal quit (which works) //the following code is slightly verbose because I'm trying to figure out what's wrong try { if (network_thread.joinable() ) { network_thread.join(); } else { TRACE("Too late!"); } } catch (boost::thread_interrupted&) { TRACE("NET INTERRUPTED"); } } The problem is that the main thread is hanging on the join, and the network thread is hanging at the end of _endthreadex. What am I misunderstanding?

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• Getting Started with Prism (aka Composite Application Guidance for WPF and Silverlight)

  - by dotneteer

  Overview Prism is a framework from the Microsoft Patterns and Practice team that allow you to create WPF and Silverlight in a modular way. It is especially valuable for larger projects in which a large number of developers can develop in parallel. Prism achieves its goal by supplying several services: · Dependency Injection (DI) and Inversion of control (IoC): By using DI, Prism takes away the responsibility of instantiating and managing the life time of dependency objects from individual components to a container. Prism relies on containers to discover, manage and compose large number of objects. By varying the configuration, the container can also inject mock objects for unit testing. Out of the box, Prism supports Unity and MEF as container although it is possible to use other containers by subclassing the Bootstrapper class. · Modularity and Region: Prism supplies the framework to split application into modules from the application shell. Each module is a library project that contains both UI and code and is responsible to initialize itself when loaded by the shell. Each window can be further divided into regions. A region is a user control with associated model. · Model, view and view-model (MVVM) pattern: Prism promotes the user MVVM. The use of DI container makes it much easier to inject model into view. WPF already has excellent data binding and commanding mechanism. To be productive with Prism, it is important to understand WPF data binding and commanding well. · Event-aggregation: Prism promotes loosely coupled components. Prism discourages for components from different modules to communicate each other, thus leading to dependency. Instead, Prism supplies an event-aggregation mechanism that allows components to publish and subscribe events without knowing each other. Architecture In the following, I will go into a little more detail on the services provided by Prism. Bootstrapper In a typical WPF application, application start-up is controls by App.xaml and its code behind. The main window of the application is typically specified in the App.xaml file. In a Prism application, we start a bootstrapper in the App class and delegate the duty of main window to the bootstrapper. The bootstrapper will start a dependency-injection container so all future object instantiations are managed by the container. Out of box, Prism provides the UnityBootstrapper and MefUnityBootstrapper abstract classes. All application needs to either provide a concrete implementation of one of these bootstrappers, or alternatively, subclass the Bootstrapper class with another DI container. A concrete bootstrapper class must implement the CreateShell method. Its responsibility is to resolve and create the Shell object through the DI container to serve as the main window for the application. The other important method to override is ConfigureModuleCatalog. The bootstrapper can register modules for the application. In a more advance scenario, an application does not have to know all its modules at compile time. Modules can be discovered at run time. Readers to refer to one of the Open Modularity Quick Starts for more information. Modules Once modules are registered with or discovered by Prism, they are instantiated by the DI container and their Initialize method is called. The DI container can inject into a module a region registry that implements IRegionViewRegistry interface. The module, in its Initialize method, can then call RegisterViewWithRegion method of the registry to register its regions. Regions Regions, once registered, are managed by the RegionManager. The shell can then load regions either through the RegionManager.RegionName attached property or dynamically through code. When a view is created by the region manager, the DI container can inject view model and other services into the view. The view then has a reference to the view model through which it can interact with backend services. Service locator Although it is possible to inject services into dependent classes through a DI container, an alternative way is to use the ServiceLocator to retrieve a service on demard. Prism supplies a service locator implementation and it is possible to get an instance of the service by calling: ServiceLocator.Current.GetInstance<IServiceType>() Event aggregator Prism supplies an IEventAggregator interface and implementation that can be injected into any class that needs to communicate with each other in a loosely-coupled fashion. The event aggregator uses a publisher/subscriber model. A class can publishes an event by calling eventAggregator.GetEvent<EventType>().Publish(parameter) to raise an event. Other classes can subscribe the event by calling eventAggregator.GetEvent<EventType>().Subscribe(EventHandler, other options). Getting started The easiest way to get started with Prism is to go through the Prism Hands-On labs and look at the Hello World QuickStart. The Hello World QuickStart shows how bootstrapper, modules and region works. Next, I would recommend you to look at the Stock Trader Reference Implementation. It is a more in depth example that resemble we want to set up an application. Several other QuickStarts cover individual Prism services. Some scenarios, such as dynamic module discovery, are more advanced. Apart from the official prism document, you can get an overview by reading Glen Block’s MSDN Magazine article. I have found the best free training material is from the Boise Code Camp. To be effective with Prism, it is important to understands key concepts of WPF well first, such as the DependencyProperty system, data binding, resource, theme and ICommand. It is also important to know your DI container of choice well. I will try to explorer these subjects in depth in the future. Testimony Recently, I worked on a desktop WPF application using Prism. I had a wonderful experience with Prism. The Prism is flexible enough even in the presence of third party controls such as Telerik WPF controls. We have never encountered any significant obstacle.

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• Java generics parameters with base of the generic parameter

  - by Iulian Serbanoiu

  Hello, I am wondering if there's an elegant solution for doing this in Java (besides the obvious one - of declaring a different/explicit function. Here is the code: private static HashMap<String, Integer> nameStringIndexMap = new HashMap<String, Integer>(); private static HashMap<Buffer, Integer> nameBufferIndexMap = new HashMap<Buffer, Integer>(); // and a function private static String newName(Object object, HashMap<Object, Integer> nameIndexMap){ .... } The problem is that I cannot pass nameStringIndexMap or nameBufferIndexMap parameters to the function. I don't have an idea about a more elegant solution beside doing another function which explicitly wants a HashMap<String, Integer> or HashMap<Buffer, Integer> parameter. My question is: Can this be made in a more elegant solution/using generics or something similar? Thank you, Iulian

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• How-to dynamically filter model-driven LOV

  - by Frank Nimphius

  Normal 0 false false false EN-US X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} Often developers need to filter a LOV query with information obtained from an ADF Faces form or other where. The sample below shows how to define a launch popup listener configured on the launchPopupListener property of the af:inputListOfValues component to filter a list of values. <af:inputListOfValues id="departmentIdId"    value="#{bindings.DepartmentId.inputValue}"                                          model="#{bindings.DepartmentId.listOfValuesModel}"    launchPopupListener="#{PopupLauncher.onPopupLaunch}" … >         … </af:inputListOfValues> A list of values is queried using a search binding that gets created in the PageDef file of a view when a lis of value component gets added. The managed bean code below looks this search binding up to then add a view criteria that filters the query. Note: There is no public API yet available for the FacesCtrlLOVBinding class, which is why I use the internal package class it in the example. public void onPopupLaunch(LaunchPopupEvent launchPopupEvent) {   BindingContext bctx = BindingContext.getCurrent();   BindingContainer bindings = bctx.getCurrentBindingsEntry();   FacesCtrlLOVBinding lov =        (FacesCtrlLOVBinding)bindings.get("DepartmentId");   ViewCriteriaManager vcm =   lov.getListIterBinding().getViewObject().getViewCriteriaManager();             //make sure the view criteria is cleared   vcm.removeViewCriteria(vcm.DFLT_VIEW_CRITERIA_NAME);   //create a new view criteria   ViewCriteria vc =          new ViewCriteria(lov.getListIterBinding().getViewObject());   //use the default view criteria name   //"__DefaultViewCriteria__"   vc.setName(vcm.DFLT_VIEW_CRITERIA_NAME);   //create a view criteria row for all queryable attributes   ViewCriteriaRow vcr = new ViewCriteriaRow(vc);   //for this sample I set the query filter to DepartmentId 60.   //You may determine it at runtime by reading it from a managed bean   //or binding layer   vcr.setAttribute("DepartmentId", 60);   //also note that the view criteria row consists of all attributes   //that belong to the LOV list view object, which means that you can   //filter on multiple attributes   vc.addRow(vcr);             lov.getListIterBinding().getViewObject().applyViewCriteria(vc); }  Note: Instead of using the vcm.DFLT_VIEW_CRITERIA_NAME name you can also define a custom name for the view criteria.

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• C# unit test code questions

  - by 5YrsLaterDBA

  We start use C# build-in unit test functionality. I have VisualStudio 2008 created unit test code for me. I have few question above the generated code. Following are code I copied from the generated file: #region Additional test attributes // //You can use the following additional attributes as you write your tests: // //Use ClassInitialize to run code before running the first test in the class //[ClassInitialize()] //public static void MyClassInitialize(TestContext testContext) //{ //} // //Use ClassCleanup to run code after all tests in a class have run //[ClassCleanup()] //public static void MyClassCleanup() //{ //} // //Use TestInitialize to run code before running each test //[TestInitialize()] //public void MyTestInitialize() //{ //} // //Use TestCleanup to run code after each test has run //[TestCleanup()] //public void MyTestCleanup() //{ //} // #endregion If I need the initialize and cleanup methods, do I need to remove those "My" from the method name when I enable them? //Use ClassInitialize to run code before running the first test in the class //[ClassInitialize()] //public static void MyClassInitialize(TestContext testContext) //{ //} Do I need to call the "MyClassInitialize" method somewhere before running the first test or it will be called automatically before other methods are called. Similar questions for other three methods, are they called automatically at right time frame?

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• SCJP question: Method ambiguous

  - by Markos Fragkakis

  Take a look at this code: public class Test { public static void main(String... args) { flipFlop("hello", new Integer(4), 2004); // flipFlop("hello", 10, 2004); // this works! } private static void flipFlop(String str, int i, Integer iRef) { System.out.println(str + " (String, int, Integer)"); } private static void flipFlop(String str, int i, int j) { System.out.println(str + " (String, int, int)"); } } The compiler gives an error that the invocation is ambiguous: Description Resource Path Location Type The method flipFlop(String, int, Integer) is ambiguous for the type Test Test.java scjp19 - inheritence/src line 3 Java Problem But if the commented-out line is used ti invoke flip-flop, the method is unambiguously invoked (the second one, because autoboxing comes after using the primitive itself). I would expect the compiler to see that the second argument will be unboxed one way or the other, and judge what method must be invoked depending on the third argument. Why does not this happen? What is the rationale?

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• How to make QT support HTML 5 database?

  - by Mickey Shine

  I am using Qt 4.7.1 and embedded a webview in my app. But I got the following error when trying to visit http://webkit.org/demos/sticky-notes/ to test the HTML 5 database feature Failed to open the database on disk. This is probably because the version was bad or there is not enough space left in this domain's quota I compiled my static Qt library with the following command: configure --prefix=/usr/local/qt-static-release-db --accessibility --multimedia --audio-backend --svg --webkit --javascript-jit --script --scripttools --declarative --release -nomake examples -nomake demos --static --openssl -I /usr/local/ssl/include -L /usr/local/ssl/lib -confirm-license -sql-qsqlite -sql-qmysql -sql-qodbc

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• jump search algorithm

  - by davit-datuashvili

  i am doing jump search algorithm but it show me that element is not in array while it is here is code import java.math.*; public class jamp { public static int min(int a,int b){ return a } public static void main(String[]args){ int a[]=new int[]{3,7,9,12,14,15,16,17,18}; int l=14; System.out.println(jumpsearch(a,a.length,l)); } public static int jumpsearch(int a[],int n, int l ){ int t=0; int b=(int)Math.sqrt(n); while (a[min(b,n)-1]=n) return -1 ; } while (a[t] return -1 ; if ( a[t]==l) { return t; } } return -1; } } please help

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• Pass Data to Data Template Selector

  - by Michael Sync

  How do you guys pass the data (parameter) to DataTemplate Selector? The only one that I can think of is to use an attached property in DataTemplate Selector? Example: public class DisableWeekendsSelection : DataTemplateSelector { [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2211:NonConstantFieldsShouldNotBeVisible", Justification = "DependencyProperty")] public static readonly DependencyProperty Parameter = DependencyProperty.RegisterAttached("Parameter", typeof(ObservableCollection<Date>), typeof(DisableWeekendsSelection), new FrameworkPropertyMetadata(null, FrameworkPropertyMetadataOptions.BindsTwoWayByDefault)); public static ObservableCollection<Date> GetParameter(DependencyObject dp) { return dp.GetValue(Parameter) as ObservableCollection<Date>; } public static void SetParameter(DependencyObject dp, ObservableCollection<Date> value) { dp.SetValue(Parameter, value); } public override DataTemplate SelectTemplate(object item, DependencyObject container) { The problem with this approach is that I'm not able to get the value of Parameter in SelectTemplate method. Any suggestion would be appreciated. Thanks in advance.

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• Array of pointers in objective-c

  - by Justin

  I'm getting confused by pointers in objective-c. Basically I have a bunch of static data in my code. static int dataSet0[2][2] = {{0, 1}, {2, 3}}; static int dataSet1[2][2] = {{4, 5}, {6, 7}}; And I want to have an array to index it all. dataSets[0]; //Would give me dataSet0... What should the type of dataSets be, and how would I initialize it?

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• Grails: Problem with nested associations in criteria builder

  - by Mr.B

  I have a frustrating problem with the criteria builder. I have an application in which one user has one calendar, and a calendar has many entries. Seems straightforward enough, but when I try to get the calendar entries for a given user, I can't access the user property (MissingMethodException). Here's the code: def getEntries(User user) { def entries = Entries.createCriteria().list() { calendar { user { eq("user.id", user.id) } } } } I have even tried the following variation: def getEntries(User user) { def entries = Entries.createCriteria().list() { calendar { eq("user", user) } } } That did not raise an exception, but didn't work either. Here's the relevant parts of the domain classes: class Calendar { static belongsTo = [user: User] static hasMany = [entries: Entries] ... } class User { Calendar calendar ... } class Entry { static belongsTo = [calendar: Calendar] ... } When Googling I came across a similar problem noted in early 2008: http://jira.codehaus.org/browse/GRAILS-1412 But according to that link this issue should have been solved long ago. What am I doing wrong?

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• algorithm diagram

  - by tunl

  This is the max searching algorithm diagram: So, I wonder how can draw diagram for Recursion in HaNoi Tower program: package tunl; public class TowersApp { static int n = 3; public static void main(String[] args) { TowersApp.doTowers(3, 'A', 'B', 'C'); } public static void doTowers(int n, char from, char inter, char to) { if (n == 1) { System.out.println("disk 1 from "+ from + " to " + to); } else { doTowers(n-1, from, to, inter); System.out.println("disk " + n + " from " + from + " to " + to); doTowers(n-1, inter, from, to); } } } I can't draw it. Anyone can help me !!!

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• NHibernate mapping error SQL Server 2008 Express

  - by developer

  Hi All, I tried an example from NHibernate in Action book and when I try to run the app, it throws an exception saying "Could not compile the mapping document: HelloNHibernate.Employee.hbm.xml" Below is my code, Employee.hbm.xml <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" auto-import="true"> <class name="HelloNHibernate.Employee, HelloNHibernate" lazy="false" table="Employee"> <id name="id" access="field"> <generator class="native"/> </id> <property name="name" access="field" column="name"/> <many-to-one access="field" name="manager" column="manager" cascade="all"/> </class> Program.cs using System; using System.Collections.Generic; using System.Linq; using System.Text; using NHibernate; using System.Reflection; using NHibernate.Cfg; namespace HelloNHibernate { class Program { static void Main(string[] args) { CreateEmployeeAndSaveToDatabase(); UpdateTobinAndAssignPierreHenriAsManager(); LoadEmployeesFromDatabase(); Console.WriteLine("Press any key to exit..."); Console.ReadKey(); } static void CreateEmployeeAndSaveToDatabase() { Employee tobin = new Employee(); tobin.name = "Tobin Harris"; using (ISession session = OpenSession()) { using (ITransaction transaction = session.BeginTransaction()) { session.Save(tobin); transaction.Commit(); } Console.WriteLine("Saved Tobin to the database"); } } static ISession OpenSession() { if (factory == null) { Configuration c = new Configuration(); c.AddAssembly(Assembly.GetCallingAssembly()); factory = c.BuildSessionFactory(); } return factory.OpenSession(); } static void LoadEmployeesFromDatabase() { using (ISession session = OpenSession()) { IQuery query = session.CreateQuery("from Employee as emp order by emp.name asc"); IList<Employee> foundEmployees = query.List<Employee>(); Console.WriteLine("\n{0} employees found:", foundEmployees.Count); foreach (Employee employee in foundEmployees) Console.WriteLine(employee.SayHello()); } } static void UpdateTobinAndAssignPierreHenriAsManager() { using (ISession session = OpenSession()) { using (ITransaction transaction = session.BeginTransaction()) { IQuery q = session.CreateQuery("from Employee where name='Tobin Harris'"); Employee tobin = q.List<Employee>()[0]; tobin.name = "Tobin David Harris"; Employee pierreHenri = new Employee(); pierreHenri.name = "Pierre Henri Kuate"; tobin.manager = pierreHenri; transaction.Commit(); Console.WriteLine("Updated Tobin and added Pierre Henri"); } } } static ISessionFactory factory; } } Employee.cs using System; using System.Collections.Generic; using System.Linq; using System.Text; namespace HelloNHibernate { class Employee { public int id; public string name; public Employee manager; public string SayHello() { return string.Format("'Hello World!', said {0}.", name); } } } App.config <?xml version="1.0" encoding="utf-8" ?> <configuration> <configSections> <section name="hibernate-configuration" type="NHibernate.Cfg.ConfigurationSectionHandler,NHibernate"/> </configSections> <hibernate-configuration xmlns="urn:nhibernate-configuration-2.2"> <session-factory> <property name="connection.provider">NHibernate.Connection.DriverConnectionProvider</property> <property name="connection.driver_class">NHibernate.Driver.SqlClientDriver</property> <property name="connection.connection_string"> Data Source=SQLEXPRESS2008;Integrated Security=True; User ID=SQL2008;Password=;initial catalog=HelloNHibernate </property> <property name="dialect">NHibernate.Dialect.MsSql2008Dialect</property> <property name="show_sql">false</property> </session-factory> </hibernate-configuration> </configuration>

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• Yet another blog about IValueConverter

  - by codingbloke

  After my previous blog on a Generic Boolean Value Converter I thought I might as well blog up another IValueConverter implementation that I use. The Generic Boolean Value Converter effectively converters an input which only has two possible values to one of two corresponding objects.  The next logical step would be to create a similar converter that can take an input which has multiple (but finite and discrete) values to one of multiple corresponding objects.  To put it more simply a Generic Enum Value Converter. Now we already have a tool that can help us in this area, the ResourceDictionary.  A simple IValueConverter implementation around it would create a StringToObjectConverter like so:- StringToObjectConverter using System; using System.Windows; using System.Windows.Data; using System.Linq; using System.Windows.Markup; namespace SilverlightApplication1 {     [ContentProperty("Items")]     public class StringToObjectConverter : IValueConverter     {         public ResourceDictionary Items { get; set; }         public string DefaultKey { get; set; }                  public StringToObjectConverter()         {             DefaultKey = "__default__";         }         public virtual object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             if (value != null && Items.Contains(value.ToString()))                 return Items[value.ToString()];             else                 return Items[DefaultKey];         }         public virtual object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             return Items.FirstOrDefault(kvp => value.Equals(kvp.Value)).Key;         }     } } There are some things to note here.  The bulk of managing the relationship between an object instance and the related string key is handled by the Items property being an ResourceDictionary.  Also there is a catch all “__default__” key value which allows for only a subset of the possible input values to mapped to an object with the rest falling through to the default. We can then set one of these up in Xaml:-             <local:StringToObjectConverter x:Key="StatusToBrush">                 <ResourceDictionary>                     <SolidColorBrush Color="Red" x:Key="Overdue" />                     <SolidColorBrush Color="Orange" x:Key="Urgent" />                     <SolidColorBrush Color="Silver" x:Key="__default__" />                 </ResourceDictionary>             </local:StringToObjectConverter> You could well imagine that in the model being bound these key names would actually be members of an enum.  This still works due to the use of ToString in the Convert method.  Hence the only requirement for the incoming object is that it has a ToString implementation which generates a sensible string instead of simply the type name. I can’t imagine right now a scenario where this converter would be used in a TwoWay binding but there is no reason why it can’t.  I prefer to avoid leaving the ConvertBack throwing an exception if that can be be avoided.  Hence it just enumerates the KeyValuePair entries to find a value that matches and returns the key its mapped to. Ah but now my sense of balance is assaulted again.  Whilst StringToObjectConverter is quite happy to accept an enum type via the Convert method it returns a string from the ConvertBack method not the original input enum type that arrived in the Convert.  Now I could address this by complicating the ConvertBack method and examining the targetType parameter etc.  However I prefer to a different approach, deriving a new EnumToObjectConverter class instead. EnumToObjectConverter using System; namespace SilverlightApplication1 {     public class EnumToObjectConverter : StringToObjectConverter     {         public override object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             string key = Enum.GetName(value.GetType(), value);             return base.Convert(key, targetType, parameter, culture);         }         public override object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)         {             string key = (string)base.ConvertBack(value, typeof(String), parameter, culture);             return Enum.Parse(targetType, key, false);         }     } }   This is a more belts and braces solution with specific use of Enum.GetName and Enum.Parse.  Whilst its more explicit in that the a developer has to  choose to use it, it is only really necessary when using TwoWay binding, in OneWay binding the base StringToObjectConverter would serve just as well. The observant might note that there is actually no “Generic” aspect to this solution in the end.  The use of a ResourceDictionary eliminates the need for that.

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