public speaking - Page 165

Microsoft MVP Award – Data Platform Development

- by Dane Morgridge

For those who don't already know, yesterday I received my first Microsoft MVP Award in Data Platform Development. With less than 5,000 MVPs in the world overall and about 20 in the Data Platform category, saying I am honored would be an understatement. From the first time I spoke at a code camp, I was totally hooked and have had a blast travelling around the east coast speaking at code camps and users groups. I'd like to take the time to thank Dani Diaz (@danidiaz) for the nomination and everyone who supported me, especially my wife Lisa for letting me travel and speak as much as I have and putting up with me for late nights and such. Roska Digital, my employer, also deserves a shout out for supporting me and giving me the necessary time off to get to speaking engagements. With any luck, the next year will be at least as fun if not more than the last one has. I hope to see you at a code camp or user group meeting soon! I would also like to send a congratulations to the other new Philly Area MVPs: John Angelini (@johnangelini) & Ned Ames (@nedames) You can find out more about the Microsoft MVP Award at https://mvp.support.microsoft.com/

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Adding and accessing custom sections in your C# App.config

- by deadlydog

So I recently thought I’d try using the app.config file to specify some data for my application (such as URLs) rather than hard-coding it into my app, which would require a recompile and redeploy of my app if one of our URLs changed. By using the app.config it allows a user to just open up the .config file that sits beside their .exe file and edit the URLs right there and then re-run the app; no recompiling, no redeployment necessary. I spent a good few hours fighting with the app.config and looking at examples on Google before I was able to get things to work properly. Most of the examples I found showed you how to pull a value from the app.config if you knew the specific key of the element you wanted to retrieve, but it took me a while to find a way to simply loop through all elements in a section, so I thought I would share my solutions here. Simple and Easy The easiest way to use the app.config is to use the built-in types, such as NameValueSectionHandler. For example, if we just wanted to add a list of database server urls to use in my app, we could do this in the app.config file like so: 1: <?xml version="1.0" encoding="utf-8" ?> 2: <configuration> 3: <configSections> 4: <section name="ConnectionManagerDatabaseServers" type="System.Configuration.NameValueSectionHandler" /> 5: </configSections> 6: <startup> 7: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> 8: </startup> 9: <ConnectionManagerDatabaseServers> 10: <add key="localhost" value="localhost" /> 11: <add key="Dev" value="Dev.MyDomain.local" /> 12: <add key="Test" value="Test.MyDomain.local" /> 13: <add key="Live" value="Prod.MyDomain.com" /> 14: </ConnectionManagerDatabaseServers> 15: </configuration> And then you can access these values in code like so: 1: string devUrl = string.Empty; 2: var connectionManagerDatabaseServers = ConfigurationManager.GetSection("ConnectionManagerDatabaseServers") as NameValueCollection; 3: if (connectionManagerDatabaseServers != null) 4: { 5: devUrl = connectionManagerDatabaseServers["Dev"].ToString(); 6: } Sometimes though you don’t know what the keys are going to be and you just want to grab all of the values in that ConnectionManagerDatabaseServers section. In that case you can get them all like this: 1: // Grab the Environments listed in the App.config and add them to our list. 2: var connectionManagerDatabaseServers = ConfigurationManager.GetSection("ConnectionManagerDatabaseServers") as NameValueCollection; 3: if (connectionManagerDatabaseServers != null) 4: { 5: foreach (var serverKey in connectionManagerDatabaseServers.AllKeys) 6: { 7: string serverValue = connectionManagerDatabaseServers.GetValues(serverKey).FirstOrDefault(); 8: AddDatabaseServer(serverValue); 9: } 10: } And here we just assume that the AddDatabaseServer() function adds the given string to some list of strings. So this works great, but what about when we want to bring in more values than just a single string (or technically you could use this to bring in 2 strings, where the “key” could be the other string you want to store; for example, we could have stored the value of the Key as the user-friendly name of the url). More Advanced (and more complicated) So if you want to bring in more information than a string or two per object in the section, then you can no longer simply use the built-in System.Configuration.NameValueSectionHandler type provided for us. Instead you have to build your own types. Here let’s assume that we again want to configure a set of addresses (i.e. urls), but we want to specify some extra info with them, such as the user-friendly name, if they require SSL or not, and a list of security groups that are allowed to save changes made to these endpoints. So let’s start by looking at the app.config: 1: <?xml version="1.0" encoding="utf-8" ?> 2: <configuration> 3: <configSections> 4: <section name="ConnectionManagerDataSection" type="ConnectionManagerUpdater.Data.Configuration.ConnectionManagerDataSection, ConnectionManagerUpdater" /> 5: </configSections> 6: <startup> 7: <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5" /> 8: </startup> 9: <ConnectionManagerDataSection> 10: <ConnectionManagerEndpoints> 11: <add name="Development" address="Dev.MyDomain.local" useSSL="false" /> 12: <add name="Test" address="Test.MyDomain.local" useSSL="true" /> 13: <add name="Live" address="Prod.MyDomain.com" useSSL="true" securityGroupsAllowedToSaveChanges="ConnectionManagerUsers" /> 14: </ConnectionManagerEndpoints> 15: </ConnectionManagerDataSection> 16: </configuration> The first thing to notice here is that my section is now using the type “ConnectionManagerUpdater.Data.Configuration.ConnectionManagerDataSection” (the fully qualified path to my new class I created) “, ConnectionManagerUpdater” (the name of the assembly my new class is in). Next, you will also notice an extra layer down in the <ConnectionManagerDataSection> which is the <ConnectionManagerEndpoints> element. This is a new collection class that I created to hold each of the Endpoint entries that are defined. Let’s look at that code now: 1: using System; 2: using System.Collections.Generic; 3: using System.Configuration; 4: using System.Linq; 5: using System.Text; 6: using System.Threading.Tasks; 7: 8: namespace ConnectionManagerUpdater.Data.Configuration 9: { 10: public class ConnectionManagerDataSection : ConfigurationSection 11: { 12: /// <summary> 13: /// The name of this section in the app.config. 14: /// </summary> 15: public const string SectionName = "ConnectionManagerDataSection"; 16: 17: private const string EndpointCollectionName = "ConnectionManagerEndpoints"; 18: 19: [ConfigurationProperty(EndpointCollectionName)] 20: [ConfigurationCollection(typeof(ConnectionManagerEndpointsCollection), AddItemName = "add")] 21: public ConnectionManagerEndpointsCollection ConnectionManagerEndpoints { get { return (ConnectionManagerEndpointsCollection)base[EndpointCollectionName]; } } 22: } 23: 24: public class ConnectionManagerEndpointsCollection : ConfigurationElementCollection 25: { 26: protected override ConfigurationElement CreateNewElement() 27: { 28: return new ConnectionManagerEndpointElement(); 29: } 30: 31: protected override object GetElementKey(ConfigurationElement element) 32: { 33: return ((ConnectionManagerEndpointElement)element).Name; 34: } 35: } 36: 37: public class ConnectionManagerEndpointElement : ConfigurationElement 38: { 39: [ConfigurationProperty("name", IsRequired = true)] 40: public string Name 41: { 42: get { return (string)this["name"]; } 43: set { this["name"] = value; } 44: } 45: 46: [ConfigurationProperty("address", IsRequired = true)] 47: public string Address 48: { 49: get { return (string)this["address"]; } 50: set { this["address"] = value; } 51: } 52: 53: [ConfigurationProperty("useSSL", IsRequired = false, DefaultValue = false)] 54: public bool UseSSL 55: { 56: get { return (bool)this["useSSL"]; } 57: set { this["useSSL"] = value; } 58: } 59: 60: [ConfigurationProperty("securityGroupsAllowedToSaveChanges", IsRequired = false)] 61: public string SecurityGroupsAllowedToSaveChanges 62: { 63: get { return (string)this["securityGroupsAllowedToSaveChanges"]; } 64: set { this["securityGroupsAllowedToSaveChanges"] = value; } 65: } 66: } 67: } So here the first class we declare is the one that appears in the <configSections> element of the app.config. It is ConnectionManagerDataSection and it inherits from the necessary System.Configuration.ConfigurationSection class. This class just has one property (other than the expected section name), that basically just says I have a Collection property, which is actually a ConnectionManagerEndpointsCollection, which is the next class defined. The ConnectionManagerEndpointsCollection class inherits from ConfigurationElementCollection and overrides the requied fields. The first tells it what type of Element to create when adding a new one (in our case a ConnectionManagerEndpointElement), and a function specifying what property on our ConnectionManagerEndpointElement class is the unique key, which I’ve specified to be the Name field. The last class defined is the actual meat of our elements. It inherits from ConfigurationElement and specifies the properties of the element (which can then be set in the xml of the App.config). The “ConfigurationProperty” attribute on each of the properties tells what we expect the name of the property to correspond to in each element in the app.config, as well as some additional information such as if that property is required and what it’s default value should be. Finally, the code to actually access these values would look like this: 1: // Grab the Environments listed in the App.config and add them to our list. 2: var connectionManagerDataSection = ConfigurationManager.GetSection(ConnectionManagerDataSection.SectionName) as ConnectionManagerDataSection; 3: if (connectionManagerDataSection != null) 4: { 5: foreach (ConnectionManagerEndpointElement endpointElement in connectionManagerDataSection.ConnectionManagerEndpoints) 6: { 7: var endpoint = new ConnectionManagerEndpoint() { Name = endpointElement.Name, ServerInfo = new ConnectionManagerServerInfo() { Address = endpointElement.Address, UseSSL = endpointElement.UseSSL, SecurityGroupsAllowedToSaveChanges = endpointElement.SecurityGroupsAllowedToSaveChanges.Split(',').Where(e => !string.IsNullOrWhiteSpace(e)).ToList() } }; 8: AddEndpoint(endpoint); 9: } 10: } This looks very similar to what we had before in the “simple” example. The main points of interest are that we cast the section as ConnectionManagerDataSection (which is the class we defined for our section) and then iterate over the endpoints collection using the ConnectionManagerEndpoints property we created in the ConnectionManagerDataSection class. Also, some other helpful resources around using app.config that I found (and for parts that I didn’t really explain in this article) are: How do you use sections in C# 4.0 app.config? (Stack Overflow) <== Shows how to use Section Groups as well, which is something that I did not cover here, but might be of interest to you. How to: Create Custom Configuration Sections Using Configuration Section (MSDN) ConfigurationSection Class (MSDN) ConfigurationCollectionAttribute Class (MSDN) ConfigurationElementCollection Class (MSDN) I hope you find this helpful. Feel free to leave a comment. Happy Coding!

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Azure Florida Association

- by Dave Noderer

Herve Roggero, SQL Azure MVP, has created a virtual community to focus on Azure. Here is the outline from Herve: User Group Name: Azure Florida Association Purpose: Start a virtual Florida user group that targets the Azure platform Venues: Most meetings will be virtual; however I plan to host a few physical events across Florida if possible from time to time; physical events may be a few hours long with potentially more than one speaker Possible Topics: The topics will touch Azure generally speaking, but can have a wide array of concern such as Integration, Data Migration, Hosting, Security, Scalability, Mobile Device integration, successful ventures/lessons learned, cross cloud integration patterns, testing in the cloud, deployment management, reporting… Target Members: Architects, Developers, IT Managers Membership: Membership will be free; virtual events will be free; physical events may involve a minimal cover charge Speakers: If you are interested in speaking or if you have topic ideas, please let me know Frequency: Initially these meetings will be held every other month The first meeting will be held on January 25, 2012 at 4PM EST. Vikas Sahni, SQL Azure MVP, will be presenting on Demystifying SQL Azure. Vikas will introduce SQL Azure, value proposition, usage scenarios, concepts and architecture, what is there and what is not, including Tips and Tricks. The actual meeting link will be available in January but please join the linked in group now to be kept informed of this and future events: http://www.linkedin.com/groups?gid=4177626.

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ASP.NET MVC 2 from Scratch – Part 1 Listing Data from Database

- by Max

Part 1 - Listing Data from Database: Let us now learn ASP.NET MVC 2 from Scratch by actually developing a front end website for the Chinook database, which is an alternative to the traditional Northwind database. You can get the Chinook database from here. As always the best way to learn something is by working on it and doing something. The Chinook database has the following schema, a quick look will help us implementing the application in a efficient way. Let us first implement a grid view table with the list of Employees with some details, this table also has the Details, Edit and Delete buttons on it to do some operations. This is series of post will concentrate on creating a simple CRUD front end for Chinook DB using ASP.NET MVC 2. In this post, we will look at listing all the possible Employees in the database in a tabular format, from which, we can then edit and delete them as required. In this post, we will concentrate on setting up our environment and then just designing a page to show a tabular information from the database. We need to first setup the SQL Server database, you can download the required version and then set it up in your localhost. Then we need to add the LINQ to SQL Classes required for us to enable interaction with our database. Now after you do the above step, just use your Server Explorer in VS 2010 to actually navigate to the database, expand the tables node and then drag drop all the tables onto the Object Relational Designer space and you go you will have the tables visualized as classes. As simple as that. Now for the purpose of displaying the data from Employee in a table, we will show only the EmployeeID, Firstname and lastname. So let us create a class to hold this information. So let us add a new class called EmployeeList to the ViewModels. We will send this data model to the View and this can be displayed in the page. public class EmployeeList { public int EmployeeID { get; set; } public string Firstname { get; set; } public string Lastname { get; set; } public EmployeeList(int empID, string fname, string lname) { this.EmployeeID = empID; this.Firstname = fname; this.Lastname = lname; } } Ok now we have got the backend ready. Let us now look at the front end view now. We will first create a master called Site.Master and reuse it across the site. The Site.Master content will be <%@ Master Language="C#" AutoEventWireup="true" CodeBehind="Site.Master.cs" Inherits="ChinookMvcSample.Views.Shared.Site" %> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head id="Head1" runat="server"> <title></title> <style type="text/css"> html { background-color: gray; } .content { width: 880px; position: relative; background-color: #ffffff; min-width: 880px; min-height: 800px; float: inherit; text-align: justify; } </style> <script src="../../Scripts/jquery-1.4.1.min.js" type="text/javascript"></script> <asp:ContentPlaceHolder ID="head" runat="server"> </asp:ContentPlaceHolder> </head> <body> <center> <h1> My Website</h1> <div class="content"> <asp:ContentPlaceHolder ID="body" runat="server"> </asp:ContentPlaceHolder> </div> </center> </body> </html> The backend Site.Master.cs does not contain anything. In the actual Index.aspx view, we add the code to simply iterate through the collection of EmployeeList that was sent to the View via the Controller. So in the top of the Index.aspx view, we have this inherits which says Inherits="System.Web.Mvc.ViewPage<IEnumerable<ChinookMvcSample.ViewModels.EmployeeList>>" In this above line, we dictate that the page is consuming a IEnumerable collection of EmployeeList. So once we specify this and compile the project. Then in our Index.aspx page, we can consume the EmployeeList object and access all its methods and properties. <table class="styled" cellpadding="3" border="0" cellspacing="0"> <tr> <th colspan="3"> </th> <th> First Name </th> <th> Last Name </th> </tr> <% foreach (var item in Model) { %> <tr> <td align="center"> <%: Html.ActionLink("Edit", "Edit", new { id = item.EmployeeID }, new { id = "links" })%> </td> <td align="center"> <%: Html.ActionLink("Details", "Details", new { id = item.EmployeeID }, new { id = "links" })%> </td> <td align="center"> <%: Html.ActionLink("Delete", "Delete", new { id = item.EmployeeID }, new { id = "links" })%> </td> <td> <%: item.Firstname %> </td> <td> <%: item.Lastname %> </td> </tr> <% } %> <tr> <td colspan="5"> <%: Html.ActionLink("Create New", "Create") %> </td> </tr> </table> The Html.ActionLink is a Html Helper to a create a hyperlink in the page, in the one we have used, the first parameter is the text that is to be used for the hyperlink, second one is the action name, third one is the parameter to be passed, last one is the attributes to be added while the hyperlink is rendered in the page. Here we are adding the id=”links” to the hyperlinks that is created in the page. In the index.aspx page, we add some jQuery stuff add alternate row colours and highlight colours for rows on mouse over. Now the Controller that handles the requests and directs the request to the right view. For the index view, the controller would be public ActionResult Index() { //var Employees = from e in data.Employees select new EmployeeList(e.EmployeeId,e.FirstName,e.LastName); //return View(Employees.ToList()); return View(_data.Employees.Select(p => new EmployeeList(p.EmployeeId, p.FirstName, p.LastName))); } Let us also write a unit test using NUnit for the above, just testing EmployeeController’s Index. DataClasses1DataContext _data; public EmployeeControllerTest() { _data = new DataClasses1DataContext("Data Source=(local);Initial Catalog=Chinook;Integrated Security=True"); } [Test] public void TestEmployeeIndex() { var e = new EmployeeController(_data); var result = e.Index() as ViewResult; var employeeList = result.ViewData.Model; Assert.IsNotNull(employeeList, "Result is null."); } In the first EmployeeControllerTest constructor, we set the data context to be used while running the tests. And then in the actual test, We just ensure that the View results returned by Index is not null. Here is the zip of the entire solution files until this point. Let me know if you have any doubts or clarifications. Cheers! Have a nice day.

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Adventures in Windows 8: Placing items in a GridView with a ColumnSpan or RowSpan

- by Laurent Bugnion

Currently working on a Windows 8 app for an important client, I will be writing about small issues, tips and tricks, ideas and whatever occurs to me during the development and the integration of this app. When working with a GridView, it is quite common to use a VariableSizedWrapGrid as the ItemsPanel. This creates a nice flowing layout which will auto-adapt for various resolutions. This is ideal when you want to build views like the Windows 8 start menu. However immediately we notice that the Start menu allows to place items on one column (Smaller) or two columns (Larger). This switch happens through the AppBar. So how do we implement that in our app? Using ColumnSpan and RowSpan When you use a VariableSizedWrapGrid directly in your XAML, you can attach the VariableSizedWrapGrid.ColumnSpan and VariableSizedWrapGrid.RowSpan attached properties directly to an item to create the desired effect. For instance this code create this output (shown in Blend but it runs just the same): <VariableSizedWrapGrid ItemHeight="100" ItemWidth="100" Width="200" Orientation="Horizontal"> <Rectangle Fill="Purple" /> <Rectangle Fill="Orange" /> <Rectangle Fill="Yellow" VariableSizedWrapGrid.ColumnSpan="2" /> <Rectangle Fill="Red" VariableSizedWrapGrid.ColumnSpan="2" VariableSizedWrapGrid.RowSpan="2" /> <Rectangle Fill="Green" VariableSizedWrapGrid.RowSpan="2" /> <Rectangle Fill="Blue" /> <Rectangle Fill="LightGray" /> </VariableSizedWrapGrid> Using the VariableSizedWrapGrid as ItemsPanel When you use a GridView however, you typically bind the ItemsSource property to a collection, for example in a viewmodel. In that case, you want to be able to switch the ColumnSpan and RowSpan depending on properties on the item. I tried to find a way to bind the VariableSizedWrapGrid.ColumnSpan attached property on the GridView’s ItemContainerStyle template to an observable property on the item, but it didn’t work. Instead, I decided to use a StyleSelector to switch the GridViewItem’s style. Here’s how: First I added my two GridViews to my XAML as follows: <Page.Resources> <local:MainViewModel x:Key="Main" /> <DataTemplate x:Key="DataTemplate1"> <Grid Background="{Binding Brush}"> <TextBlock Text="{Binding BrushCode}" /> </Grid> </DataTemplate> </Page.Resources> <Page.DataContext> <Binding Source="{StaticResource Main}" /> </Page.DataContext> <Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}" Margin="20"> <Grid.ColumnDefinitions> <ColumnDefinition Width="Auto" /> <ColumnDefinition Width="*" /> </Grid.ColumnDefinitions> <GridView ItemsSource="{Binding Items}" ItemTemplate="{StaticResource DataTemplate1}" VerticalAlignment="Top"> <GridView.ItemsPanel> <ItemsPanelTemplate> <VariableSizedWrapGrid ItemHeight="150" ItemWidth="150" /> </ItemsPanelTemplate> </GridView.ItemsPanel> </GridView> <GridView Grid.Column="1" ItemsSource="{Binding Items}" ItemTemplate="{StaticResource DataTemplate1}" VerticalAlignment="Top"> <GridView.ItemsPanel> <ItemsPanelTemplate> <VariableSizedWrapGrid ItemHeight="100" ItemWidth="100" /> </ItemsPanelTemplate> </GridView.ItemsPanel> </GridView> </Grid> The MainViewModel looks like this: public class MainViewModel { public IList<Item> Items { get; private set; } public MainViewModel() { Items = new List<Item> { new Item { Brush = new SolidColorBrush(Colors.Red) }, new Item { Brush = new SolidColorBrush(Colors.Blue) }, new Item { Brush = new SolidColorBrush(Colors.Green), }, // And more... }; } } As for the Item class, I am using an MVVM Light ObservableObject but you can use your own simple implementation of INotifyPropertyChanged of course: public class Item : ObservableObject { public const string ColSpanPropertyName = "ColSpan"; private int _colSpan = 1; public int ColSpan { get { return _colSpan; } set { Set(ColSpanPropertyName, ref _colSpan, value); } } public SolidColorBrush Brush { get; set; } public string BrushCode { get { return Brush.Color.ToString(); } } } Then I copied the GridViewItem’s style locally. To do this, I use Expression Blend’s functionality. It has the disadvantage to copy a large portion of XAML to your application, but the HUGE advantage to allow you to change the look and feel of your GridViewItem everywhere in the application. For example, you can change the selection chrome, the item’s alignments and many other properties. Actually everytime I use a ListBox, ListView or any other data control, I typically copy the item style to a resource dictionary in my application and I tweak it. Note that Blend for Windows 8 apps is automatically installed with every edition of Visual Studio 2012 (including Express) so you have no excuses anymore not to use Blend :) Open MainPage.xaml in Expression Blend by right clicking on the MainPage.xaml file in the Solution Explorer and selecting Open in Blend from the context menu. Note that the items do not look very nice! The reason is that the default ItemContainerStyle sets the content’s alignment to “Center” which I never quite understood. Seems to me that you rather want the content to be stretched, but anyway it is easy to change. Right click on the GridView on the left and select Edit Additional Templates, Edit Generated Item Container (ItemContainerStyle), Edit a Copy. In the Create Style Resource dialog, enter the name “DefaultGridViewItemStyle”, select “Application” and press OK. Side note 1: You need to save in a global resource dictionary because later we will need to retrieve that Style from a global location. Side note 2": I would rather copy the style to an external resource dictionary that I link into the App.xaml file, but I want to keep things simple here. Blend switches in Template edit mode. The template you are editing now is inside the ItemContainerStyle and will govern the appearance of your items. This is where, for instance, the “checked” chrome is defined, and where you can alter it if you need to. Note that you can reuse this style for all your GridViews even if you use a different DataTemplate for your items. Makes sense? I probably need to think about writing another blog post dedicated to the ItemContainerStyle :) In the breadcrumb bar on top of the page, click on the style icon. The property we want to change now can be changed in the Style instead of the Template, which is a better idea. Blend is not in Style edit mode, as you can see in the Objects and Timeline pane. In the Properties pane, in the Search box, enter the word “content”. This will filter all the properties containing that partial string, including the two we are interested in: HorizontalContentAlignment and VerticalContentAlignment. Set these two values to “Stretch” instead of the default “Center”. Using the breadcrumb bar again, set the scope back to the Page (by clicking on the first crumb on the left). Notice how the items are now showing as squares in the first GridView. We will now use the same ItemContainerStyle for the second GridView. To do this, right click on the second GridView and select Edit Additional Templates, Edit Generate Item Container, Apply Resource, DefaultGridViewItemStyle. The page now looks nicer: And now for the ColumnSpan! So now, let’s change the ColumnSpan property. First, let’s define a new Style that inherits the ItemContainerStyle we created before. Make sure that you save everything in Blend by pressing Ctrl-Shift-S. Open App.xaml in Visual Studio. Below the newly created DefaultGridViewItemStyle resource, add the following style: <Style x:Key="WideGridViewItemStyle" TargetType="GridViewItem" BasedOn="{StaticResource DefaultGridViewItemStyle}"> <Setter Property="VariableSizedWrapGrid.ColumnSpan" Value="2" /> </Style> Add a new class to the project, and name it MainItemStyleSelector. Implement the class as follows: public class MainItemStyleSelector : StyleSelector { protected override Style SelectStyleCore(object item, DependencyObject container) { var i = (Item)item; if (i.ColSpan == 2) { return Application.Current.Resources["WideGridViewItemStyle"] as Style; } return Application.Current.Resources["DefaultGridViewItemStyle"] as Style; } } In MainPage.xaml, add a resource to the Page.Resources section: <local:MainItemStyleSelector x:Key="MainItemStyleSelector" /> In MainPage.xaml, replace the ItemContainerStyle property on the first GridView with the ItemContainerStyleSelector property, pointing to the StaticResource we just defined. <GridView ItemsSource="{Binding Items}" ItemTemplate="{StaticResource DataTemplate1}" VerticalAlignment="Top" ItemContainerStyleSelector="{StaticResource MainItemStyleSelector}"> <GridView.ItemsPanel> <ItemsPanelTemplate> <VariableSizedWrapGrid ItemHeight="150" ItemWidth="150" /> </ItemsPanelTemplate> </GridView.ItemsPanel> </GridView> Do the same for the second GridView as well. Finally, in the MainViewModel, change the ColumnSpan property on the 3rd Item to 2. new Item { Brush = new SolidColorBrush(Colors.Green), ColSpan = 2 }, Running the application now creates the following image, which is what we wanted. Notice how the green item is now a “wide tile”. You can also experiment by creating different Styles, all inheriting the DefaultGridViewItemStyle and using different values of RowSpan for instance. This will allow you to create any layout you want, while leaving the heavy lifting of “flowing the layout” to the GridView control. What about changing these values dynamically? Of course as we can see in the Start menu, it would be nice to be able to change the ColumnSpan and maybe even the RowSpan values at runtime. Unfortunately at this time I have not found a good way to do that. I am investigating however and will make sure to post a follow up when I find what I am looking for! Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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Rotating a NetBeans Visual Library Widget

- by Geertjan

Trying to create a widget which, when clicked, rotates slightly further on each subsequent click: Above, the bird where the mouse is visible has been clicked a few times and so has rotated a bit further on each click. The code isn't quite right yet and I'm hoping someone will take this code, try it out, and help with a nice solution! public class BirdScene extends Scene { public BirdScene() { addChild(new LayerWidget(this)); getActions().addAction(ActionFactory.createAcceptAction(new AcceptProvider() { public ConnectorState isAcceptable(Widget widget, Point point, Transferable transferable) { Image dragImage = getImageFromTransferable(transferable); if (dragImage != null) { JComponent view = getView(); Graphics2D g2 = (Graphics2D) view.getGraphics(); Rectangle visRect = view.getVisibleRect(); view.paintImmediately(visRect.x, visRect.y, visRect.width, visRect.height); g2.drawImage(dragImage, AffineTransform.getTranslateInstance(point.getLocation().getX(), point.getLocation().getY()), null); return ConnectorState.ACCEPT; } else { return ConnectorState.REJECT; } } public void accept(Widget widget, final Point point, Transferable transferable) { addChild(new BirdWidget(getScene(), getImageFromTransferable(transferable), point)); } })); } private Image getImageFromTransferable(Transferable transferable) { Object o = null; try { o = transferable.getTransferData(DataFlavor.imageFlavor); } catch (IOException ex) { } catch (UnsupportedFlavorException ex) { } return o instanceof Image ? (Image) o : null; } private class BirdWidget extends IconNodeWidget { private int theta = 0; public BirdWidget(Scene scene, Image imageFromTransferable, Point point) { super(scene); setImage(imageFromTransferable); setPreferredLocation(point); setCheckClipping(true); getActions().addAction(ActionFactory.createMoveAction()); getActions().addAction(ActionFactory.createSelectAction(new SelectProvider() { public boolean isAimingAllowed(Widget widget, Point localLocation, boolean invertSelection) { return true; } public boolean isSelectionAllowed(Widget widget, Point localLocation, boolean invertSelection) { return true; } public void select(final Widget widget, Point localLocation, boolean invertSelection) { theta = (theta + 100) % 360; repaint(); getScene().validate(); } })); } @Override public void paintWidget() { final Image image = getImageWidget().getImage(); Graphics2D g = getGraphics(); g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); Rectangle bounds = getClientArea(); AffineTransform newXform = g.getTransform(); int xRot = image.getWidth(null) / 2; int yRot = image.getWidth(null) / 2; newXform.rotate(theta * Math.PI / 180, xRot, yRot); g.setTransform(newXform); g.drawImage(image, bounds.x, bounds.y, null); } } } The problem relates to refreshing the scene after the rotation. But it would help if someone would just take the code above, add it to their own application, try it out, see the problem for yourself, and develop it a bit further!

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Life Is Full Of Changes (Part 1)

- by Brian Jackett

Today will be my last day with Sogeti. I’ve been with Sogeti USA for just over 4 years. In that time I’ve gotten to work on some great projects, develop relationships with some brilliant and passionate people, participate in the .Net developer and SharePoint communities, and grow my skills in a number of areas I’m passionate about. As with all good things they must come to an end though. I’ve accepted a position with another company and will provide more details once the transition has completed. This decision was a difficult one to make but it provides a great career opportunity on many levels. As much as my new schedule allows I plan to continue participating in local user groups, speaking at conferences, and blogging. Speaking of which, you may have noticed my reduced blogging activity in the past few months. In addition to a career change I’m also in the process of moving to a new residence (only a few miles from my current residence, so I’ll still be in Columbus.) Searching for a new place, filling out paperwork, and all of the other work associated with this move has taken away a good chunk of the time I used to devote to blogging. Once everything gets settled out with the move and job change I’ll re-evaluate how much time I can devote to blogging. A big thanks to Sogeti and everyone who has been so supportive over my time with them. It’s hard to move on, but I am excited for the prospects that the future will bring. -Frog Out

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South Florida Code Camp and Other Events

- by MOSSLover

My grandmother wanted me to make her a video when she heard I got MVP in SharePoint Server of one of my sessions. I decided I haven’t visited in two years, so maybe I can do an in person session. I googled around and found South Florida Code Camp, which will be Saturday, February 12th. I will be doing a session at 9:50 in the morning on Silverlight just for my grandmother and whoever shows up. Here is the link for more information: http://www.fladotnet.com/codecamp/. In the upcoming months I plan to return to SharePoint Saturday speaking. We are also organizing another New York event on Saturday, July 30th. We will open up submissions for sponsors and speakers somewhere after Best Practices Conference in LaJolla. I will be speaking at Best Practices LaJolla and the The Expert’s Conference in the upcoming months. I am really sorry for the lack of updates it’s just been incredibly crazy going back and forth to DC and not having internet on weekdays or having the slowest internet in the world has just not helped. I am also trying to attend Coders 4 Charity this year, so I can visit some people in St. Louis. I’ve already got an incredibly crazy schedule going for the year. I might be helping organize more events. I’m going to volunteer at New York Code Camp too doing whatever they need this year. Check back for more updates. Technorati Tags: SharePoint Conferences 2011,Events 2011

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WPF TreeView MouseDown

- by imekon

I've got something like this in a TreeView: <DataTemplate x:Key="myTemplate"> <StackPanel MouseDown="OnItemMouseDown"> ... </StackPanel> </DataTemplate> Using this I get the mouse down events if I click on items in the stack panel. However... there seems to be another item behind the stack panel that is the TreeViewItem - it's very hard to hit, but not impossible, and that's when the problems start to occur. I had a go at handling PreviewMouseDown on TreeViewItem, however that seems to require e.Handled = false otherwise standard tree view behaviour stops working. Ok, Here's the source code... MainWindow.xaml <Window x:Class="WPFMultiSelectTree.MainWindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" xmlns:local="clr-namespace:WPFMultiSelectTree" Title="Multiple Selection Tree" Height="300" Width="300"> <Window.Resources>  <local:VisibilityConverter x:Key="visibilityConverter"/> <local:VisibilityInverter x:Key="visibilityInverter"/>  <Style TargetType="TreeViewItem"> <Style.Triggers> <DataTrigger Binding="{Binding Selected}" Value="True"> <Setter Property="Background" Value="DarkBlue"/> <Setter Property="Foreground" Value="White"/> </DataTrigger> </Style.Triggers> <EventSetter Event="PreviewMouseDown" Handler="OnTreePreviewMouseDown"/> </Style>  <HierarchicalDataTemplate x:Key="RecursiveTemplate" ItemsSource="{Binding Children}"> <StackPanel Margin="2" Orientation="Horizontal" MouseDown="OnTreeMouseDown"> <Ellipse Width="12" Height="12" Fill="Green"/> <TextBlock Margin="2" Text="{Binding Name}" Visibility="{Binding Editing, Converter={StaticResource visibilityInverter}}"/> <TextBox Margin="2" Text="{Binding Name}" KeyDown="OnTextBoxKeyDown" IsVisibleChanged="OnTextBoxIsVisibleChanged" Visibility="{Binding Editing, Converter={StaticResource visibilityConverter}}"/> <TextBlock Margin="2" Text="{Binding Index, StringFormat=({0})}"/> </StackPanel> </HierarchicalDataTemplate>  <DataTemplate x:Key="ListTemplate"> <TextBlock Text="{Binding Name}"/> </DataTemplate> </Window.Resources> <Grid>  <Grid.RowDefinitions> <RowDefinition Height="Auto"/> <RowDefinition/> <RowDefinition Height="Auto"/> <RowDefinition/> </Grid.RowDefinitions>  <TextBlock Grid.Row="0" Margin="5" Background="PowderBlue">Multiple selection tree view</TextBlock>  <TreeView Name="m_tree" Margin="2" Grid.Row="1" ItemsSource="{Binding Children}" ItemTemplate="{StaticResource RecursiveTemplate}"/>  <TextBlock Grid.Row="2" Margin="5" Background="PowderBlue">The currently selected items in the tree</TextBlock>  <ListBox Name="m_list" Margin="2" Grid.Row="3" ItemsSource="{Binding .}" ItemTemplate="{StaticResource ListTemplate}"/> </Grid> </Window> MainWindow.xaml.cs /// <summary> /// Interaction logic for MainWindow.xaml /// </summary> public partial class MainWindow : Window { private Container m_root; private Container m_first; private ObservableCollection<Container> m_selection; private string m_current; /// <summary> /// Constructor /// </summary> public MainWindow() { InitializeComponent(); m_selection = new ObservableCollection<Container>(); m_root = new Container("root"); for (int parents = 0; parents < 50; parents++) { Container parent = new Container(String.Format("parent{0}", parents + 1)); for (int children = 0; children < 1000; children++) { parent.Add(new Container(String.Format("child{0}", children + 1))); } m_root.Add(parent); } m_tree.DataContext = m_root; m_list.DataContext = m_selection; m_first = null; } /// <summary> /// Has the shift key been pressed? /// </summary> private bool ShiftPressed { get { return Keyboard.IsKeyDown(Key.LeftShift) || Keyboard.IsKeyDown(Key.RightShift); } } /// <summary> /// Has the control key been pressed? /// </summary> private bool CtrlPressed { get { return Keyboard.IsKeyDown(Key.LeftCtrl) || Keyboard.IsKeyDown(Key.RightCtrl); } } /// <summary> /// Clear down the selection list /// </summary> private void DeselectAndClear() { foreach(Container container in m_selection) { container.Selected = false; } m_selection.Clear(); } /// <summary> /// Add the container to the list (if not already present), /// mark as selected /// </summary> /// <param name="container"></param> private void AddToSelection(Container container) { if (container == null) { return; } foreach (Container child in m_selection) { if (child == container) { return; } } container.Selected = true; m_selection.Add(container); } /// <summary> /// Remove container from list, mark as not selected /// </summary> /// <param name="container"></param> private void RemoveFromSelection(Container container) { m_selection.Remove(container); container.Selected = false; } /// <summary> /// Process single click on a tree item /// /// Normally just select an item /// /// SHIFT-Click extends selection /// CTRL-Click toggles a selection /// </summary> /// <param name="sender"></param> private void OnTreeSingleClick(object sender) { FrameworkElement element = sender as FrameworkElement; if (element != null) { Container container = element.DataContext as Container; if (container != null) { if (CtrlPressed) { if (container.Selected) { RemoveFromSelection(container); } else { AddToSelection(container); } } else if (ShiftPressed) { if (container.Parent == m_first.Parent) { if (container.Index < m_first.Index) { Container item = container; for (int i = container.Index; i < m_first.Index; i++) { AddToSelection(item); item = item.Next; if (item == null) { break; } } } else if (container.Index > m_first.Index) { Container item = m_first; for (int i = m_first.Index; i <= container.Index; i++) { AddToSelection(item); item = item.Next; if (item == null) { break; } } } } } else { DeselectAndClear(); m_first = container; AddToSelection(container); } } } } /// <summary> /// Process double click on tree item /// </summary> /// <param name="sender"></param> private void OnTreeDoubleClick(object sender) { FrameworkElement element = sender as FrameworkElement; if (element != null) { Container container = element.DataContext as Container; if (container != null) { container.Editing = true; m_current = container.Name; } } } /// <summary> /// Clicked on the stack panel in the tree view /// /// Double left click: /// /// Switch to editing mode (flips visibility of textblock and textbox) /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void OnTreeMouseDown(object sender, MouseButtonEventArgs e) { Debug.WriteLine("StackPanel mouse down"); switch(e.ChangedButton) { case MouseButton.Left: switch (e.ClickCount) { case 2: OnTreeDoubleClick(sender); e.Handled = true; break; } break; } } /// <summary> /// Clicked on tree view item in tree /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void OnTreePreviewMouseDown(object sender, MouseButtonEventArgs e) { Debug.WriteLine("TreeViewItem preview mouse down"); switch (e.ChangedButton) { case MouseButton.Left: switch (e.ClickCount) { case 1: { // We've had a single click on a tree view item // Unfortunately this is the WHOLE tree item, including the +/- // symbol to the left. The tree doesn't do a selection, so we // have to filter this out... MouseDevice device = e.Device as MouseDevice; Debug.WriteLine(String.Format("Tree item clicked on: {0}", device.DirectlyOver.GetType().ToString())); // This is bad. The whole point of WPF is for the code // not to know what the UI has - yet here we are testing for // it as a workaround. Sigh... if (device.DirectlyOver.GetType() != typeof(Path)) { OnTreeSingleClick(sender); } // Cannot say handled - if we do it stops the tree working! //e.Handled = true; } break; } break; } } /// <summary> /// Key press in text box /// /// Return key finishes editing /// Escape key finishes editing, restores original value (this doesn't work!) /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void OnTextBoxKeyDown(object sender, KeyEventArgs e) { switch(e.Key) { case Key.Return: { TextBox box = sender as TextBox; if (box != null) { Container container = box.DataContext as Container; if (container != null) { container.Editing = false; e.Handled = true; } } } break; case Key.Escape: { TextBox box = sender as TextBox; if (box != null) { Container container = box.DataContext as Container; if (container != null) { container.Editing = false; container.Name = m_current; e.Handled = true; } } } break; } } /// <summary> /// When text box becomes visible, grab focus and select all text in it. /// </summary> /// <param name="sender"></param> /// <param name="e"></param> private void OnTextBoxIsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e) { bool visible = (bool)e.NewValue; if (visible) { TextBox box = sender as TextBox; if (box != null) { box.Focus(); box.SelectAll(); } } } } Here's the Container class public class Container : INotifyPropertyChanged { private string m_name; private ObservableCollection<Container> m_children; private Container m_parent; private bool m_selected; private bool m_editing; /// <summary> /// Constructor /// </summary> /// <param name="name">name of object</param> public Container(string name) { m_name = name; m_children = new ObservableCollection<Container>(); m_parent = null; m_selected = false; m_editing = false; } /// <summary> /// Name of object /// </summary> public string Name { get { return m_name; } set { if (m_name != value) { m_name = value; OnPropertyChanged("Name"); } } } /// <summary> /// Index of object in parent's children /// /// If there's no parent, the index is -1 /// </summary> public int Index { get { if (m_parent != null) { return m_parent.Children.IndexOf(this); } return -1; } } /// <summary> /// Get the next item, assuming this is parented /// /// Returns null if end of list reached, or no parent /// </summary> public Container Next { get { if (m_parent != null) { int index = Index + 1; if (index < m_parent.Children.Count) { return m_parent.Children[index]; } } return null; } } /// <summary> /// List of children /// </summary> public ObservableCollection<Container> Children { get { return m_children; } } /// <summary> /// Selected status /// </summary> public bool Selected { get { return m_selected; } set { if (m_selected != value) { m_selected = value; OnPropertyChanged("Selected"); } } } /// <summary> /// Editing status /// </summary> public bool Editing { get { return m_editing; } set { if (m_editing != value) { m_editing = value; OnPropertyChanged("Editing"); } } } /// <summary> /// Parent of this object /// </summary> public Container Parent { get { return m_parent; } set { m_parent = value; } } /// <summary> /// WPF Property Changed event /// </summary> public event PropertyChangedEventHandler PropertyChanged; /// <summary> /// Handler to inform WPF that a property has changed /// </summary> /// <param name="name"></param> private void OnPropertyChanged(string name) { if (PropertyChanged != null) { PropertyChanged(this, new PropertyChangedEventArgs(name)); } } /// <summary> /// Add a child to this container /// </summary> /// <param name="child"></param> public void Add(Container child) { m_children.Add(child); child.m_parent = this; } /// <summary> /// Remove a child from this container /// </summary> /// <param name="child"></param> public void Remove(Container child) { m_children.Remove(child); child.m_parent = null; } } The two classes VisibilityConverter and VisibilityInverter are implementations of IValueConverter that translates bool to Visibility. They make sure the TextBlock is displayed when not editing, and the TextBox is displayed when editing.

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Passing data between android ListActivities in Java

- by Will Janes

I am new to Android! I am having a problem getting this code to work... Basically I Go from one list activity to another and pass the text from a list item through the intent of the activity to the new list view, then retrieve that text in the new list activity and then preform a http request based on value of that list item. Log Cat 04-05 17:47:32.370: E/AndroidRuntime(30135): FATAL EXCEPTION: main 04-05 17:47:32.370: E/AndroidRuntime(30135): java.lang.ClassCastException:android.widget.LinearLayout 04-05 17:47:32.370: E/AndroidRuntime(30135): at com.thickcrustdesigns.ufood.CatogPage$1.onItemClick(CatogPage.java:66) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.widget.AdapterView.performItemClick(AdapterView.java:284) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.widget.ListView.performItemClick(ListView.java:3731) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.widget.AbsListView$PerformClick.run(AbsListView.java:1959) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.os.Handler.handleCallback(Handler.java:587) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.os.Handler.dispatchMessage(Handler.java:92) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.os.Looper.loop(Looper.java:130) 04-05 17:47:32.370: E/AndroidRuntime(30135): at android.app.ActivityThread.main(ActivityThread.java:3691) 04-05 17:47:32.370: E/AndroidRuntime(30135): at java.lang.reflect.Method.invokeNative(Native Method) 04-05 17:47:32.370: E/AndroidRuntime(30135): at java.lang.reflect.Method.invoke(Method.java:507) 04-05 17:47:32.370: E/AndroidRuntime(30135): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:907) 04-05 17:47:32.370: E/AndroidRuntime(30135): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:665) 04-05 17:47:32.370: E/AndroidRuntime(30135): at dalvik.system.NativeStart.main(Native Method) ListActivity 1 package com.thickcrustdesigns.ufood; import java.util.ArrayList; import org.apache.http.NameValuePair; import org.apache.http.message.BasicNameValuePair; import org.json.JSONException; import org.json.JSONObject; import android.app.ListActivity; import android.content.Intent; import android.os.Bundle; import android.view.View; import android.widget.AdapterView; import android.widget.AdapterView.OnItemClickListener; import android.widget.Button; import android.widget.ListView; import android.widget.TextView; public class CatogPage extends ListActivity { ListView listView1; Button btn_bk; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.definition_main); btn_bk = (Button) findViewById(R.id.btn_bk); listView1 = (ListView) findViewById(android.R.id.list); ArrayList<NameValuePair> nvp = new ArrayList<NameValuePair>(); nvp.add(new BasicNameValuePair("request", "categories")); ArrayList<JSONObject> jsondefs = Request.fetchData(this, nvp); String[] defs = new String[jsondefs.size()]; for (int i = 0; i < jsondefs.size(); i++) { try { defs[i] = jsondefs.get(i).getString("Name"); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } uFoodAdapter adapter = new uFoodAdapter(this, R.layout.definition_list, defs); listView1.setAdapter(adapter); ListView lv = getListView(); lv.setOnItemClickListener(new OnItemClickListener() { @Override public void onItemClick(AdapterView<?> parent, View view, int position, long id) { TextView tv = (TextView) view; String p = tv.getText().toString(); Intent i = new Intent(getApplicationContext(), Results.class); i.putExtra("category", p); startActivity(i); } }); btn_bk.setOnClickListener(new View.OnClickListener() { public void onClick(View arg0) { Intent i = new Intent(getApplicationContext(), UFoodAppActivity.class); startActivity(i); } }); } } **ListActivity 2** package com.thickcrustdesigns.ufood; import java.util.ArrayList; import org.apache.http.NameValuePair; import org.apache.http.message.BasicNameValuePair; import org.json.JSONException; import org.json.JSONObject; import android.app.ListActivity; import android.os.Bundle; import android.widget.ListView; public class Results extends ListActivity { ListView listView1; enum Category { Chicken, Beef, Chinese, Cocktails, Curry, Deserts, Fish, ForOne { public String toString() { return "For One"; } }, Lamb, LightBites { public String toString() { return "Light Bites"; } }, Pasta, Pork, Vegetarian } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.setContentView(R.layout.definition_main); listView1 = (ListView) findViewById(android.R.id.list); Bundle data = getIntent().getExtras(); String category = data.getString("category"); Category cat = Category.valueOf(category); String value = null; switch (cat) { case Chicken: value = "Chicken"; break; case Beef: value = "Beef"; break; case Chinese: value = "Chinese"; break; case Cocktails: value = "Cocktails"; break; case Curry: value = "Curry"; break; case Deserts: value = "Deserts"; break; case Fish: value = "Fish"; break; case ForOne: value = "ForOne"; break; case Lamb: value = "Lamb"; break; case LightBites: value = "LightBites"; break; case Pasta: value = "Pasta"; break; case Pork: value = "Pork"; break; case Vegetarian: value = "Vegetarian"; } ArrayList<NameValuePair> nvp = new ArrayList<NameValuePair>(); nvp.add(new BasicNameValuePair("request", "category")); nvp.add(new BasicNameValuePair("cat", value)); ArrayList<JSONObject> jsondefs = Request.fetchData(this, nvp); String[] defs = new String[jsondefs.size()]; for (int i = 0; i < jsondefs.size(); i++) { try { defs[i] = jsondefs.get(i).getString("Name"); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } uFoodAdapter adapter = new uFoodAdapter(this, R.layout.definition_list, defs); listView1.setAdapter(adapter); } } Request package com.thickcrustdesigns.ufood; import java.io.BufferedReader; import java.io.InputStream; import java.io.InputStreamReader; import java.util.ArrayList; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.NameValuePair; import org.apache.http.client.HttpClient; import org.apache.http.client.entity.UrlEncodedFormEntity; import org.apache.http.client.methods.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.json.JSONArray; import org.json.JSONObject; import android.content.Context; import android.util.Log; import android.widget.Toast; public class Request { @SuppressWarnings("null") public static ArrayList<JSONObject> fetchData(Context context, ArrayList<NameValuePair> nvp) { ArrayList<JSONObject> listItems = new ArrayList<JSONObject>(); InputStream is = null; try { HttpClient httpclient = new DefaultHttpClient(); HttpPost httppost = new HttpPost( "http://co350-11d.projects02.glos.ac.uk/php/database.php"); httppost.setEntity(new UrlEncodedFormEntity(nvp)); HttpResponse response = httpclient.execute(httppost); HttpEntity entity = response.getEntity(); is = entity.getContent(); } catch (Exception e) { Log.e("log_tag", "Error in http connection" + e.toString()); } // convert response to string String result = ""; try { BufferedReader reader = new BufferedReader(new InputStreamReader( is, "iso-8859-1"), 8); InputStream stream = null; StringBuilder sb = null; while ((result = reader.readLine()) != null) { sb.append(result + "\n"); } stream.close(); result = sb.toString(); } catch (Exception e) { Log.e("log_tag", "Error converting result " + e.toString()); } try { JSONArray jArray = new JSONArray(result); for (int i = 0; i < jArray.length(); i++) { JSONObject jo = jArray.getJSONObject(i); listItems.add(jo); } } catch (Exception e) { Toast.makeText(context.getApplicationContext(), "None Found!", Toast.LENGTH_LONG).show(); } return listItems; } } Any help would be grateful! Many Thanks EDIT Sorry very tired so missed out my 2nd ListActivity package com.thickcrustdesigns.ufood; import java.util.ArrayList; import org.apache.http.NameValuePair; import org.apache.http.message.BasicNameValuePair; import org.json.JSONException; import org.json.JSONObject; import android.app.ListActivity; import android.os.Bundle; import android.widget.ListView; public class Results extends ListActivity { ListView listView1; enum Category { Chicken, Beef, Chinese, Cocktails, Curry, Deserts, Fish, ForOne { public String toString() { return "For One"; } }, Lamb, LightBites { public String toString() { return "Light Bites"; } }, Pasta, Pork, Vegetarian } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); this.setContentView(R.layout.definition_main); listView1 = (ListView) findViewById(android.R.id.list); Bundle data = getIntent().getExtras(); String category = data.getString("category"); Category cat = Category.valueOf(category); String value = null; switch (cat) { case Chicken: value = "Chicken"; break; case Beef: value = "Beef"; break; case Chinese: value = "Chinese"; break; case Cocktails: value = "Cocktails"; break; case Curry: value = "Curry"; break; case Deserts: value = "Deserts"; break; case Fish: value = "Fish"; break; case ForOne: value = "ForOne"; break; case Lamb: value = "Lamb"; break; case LightBites: value = "LightBites"; break; case Pasta: value = "Pasta"; break; case Pork: value = "Pork"; break; case Vegetarian: value = "Vegetarian"; } ArrayList<NameValuePair> nvp = new ArrayList<NameValuePair>(); nvp.add(new BasicNameValuePair("request", "category")); nvp.add(new BasicNameValuePair("cat", value)); ArrayList<JSONObject> jsondefs = Request.fetchData(this, nvp); String[] defs = new String[jsondefs.size()]; for (int i = 0; i < jsondefs.size(); i++) { try { defs[i] = jsondefs.get(i).getString("Name"); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } uFoodAdapter adapter = new uFoodAdapter(this, R.layout.definition_list, defs); listView1.setAdapter(adapter); } } Sorry again! Cheers guys!

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Convert Java program to C

- by imicrothinking

I need a bit of guidance with writing a C program...a bit of quick background as to my level, I've programmed in Java previously, but this is my first time programming in C, and we've been tasked to translate a word count program from Java to C that consists of the following: Read a file from memory Count the words in the file For each occurrence of a unique word, keep a word counter variable Print out the top ten most frequent words and their corresponding occurrences Here's the source program in Java: package lab0; import java.io.File; import java.io.FileReader; import java.util.ArrayList; import java.util.Calendar; import java.util.Collections; public class WordCount { private ArrayList<WordCountNode> outputlist = null; public WordCount(){ this.outputlist = new ArrayList<WordCountNode>(); } /** * Read the file into memory. * * @param filename name of the file. * @return content of the file. * @throws Exception if the file is too large or other file related exception. */ public char[] readFile(String filename) throws Exception{ char [] result = null; File file = new File(filename); long size = file.length(); if (size > Integer.MAX_VALUE){ throw new Exception("File is too large"); } result = new char[(int)size]; FileReader reader = new FileReader(file); int len, offset = 0, size2read = (int)size; while(size2read > 0){ len = reader.read(result, offset, size2read); if(len == -1) break; size2read -= len; offset += len; } return result; } /** * Make article word by word. * * @param article the content of file to be counted. * @return string contains only letters and "'". */ private enum SPLIT_STATE {IN_WORD, NOT_IN_WORD}; /** * Go through article, find all the words and add to output list * with their count. * * @param article the content of the file to be counted. * @return words in the file and their counts. */ public ArrayList<WordCountNode> countWords(char[] article){ SPLIT_STATE state = SPLIT_STATE.NOT_IN_WORD; if(null == article) return null; char curr_ltr; int curr_start = 0; for(int i = 0; i < article.length; i++){ curr_ltr = Character.toUpperCase( article[i]); if(state == SPLIT_STATE.IN_WORD){ article[i] = curr_ltr; if ((curr_ltr < 'A' || curr_ltr > 'Z') && curr_ltr != '\'') { article[i] = ' '; //printf("\nthe word is %s\n\n",curr_start); if(i - curr_start < 0){ System.out.println("i = " + i + " curr_start = " + curr_start); } addWord(new String(article, curr_start, i-curr_start)); state = SPLIT_STATE.NOT_IN_WORD; } }else{ if (curr_ltr >= 'A' && curr_ltr <= 'Z') { curr_start = i; article[i] = curr_ltr; state = SPLIT_STATE.IN_WORD; } } } return outputlist; } /** * Add the word to output list. */ public void addWord(String word){ int pos = dobsearch(word); if(pos >= outputlist.size()){ outputlist.add(new WordCountNode(1L, word)); }else{ WordCountNode tmp = outputlist.get(pos); if(tmp.getWord().compareTo(word) == 0){ tmp.setCount(tmp.getCount() + 1); }else{ outputlist.add(pos, new WordCountNode(1L, word)); } } } /** * Search the output list and return the position to put word. * @param word is the word to be put into output list. * @return position in the output list to insert the word. */ public int dobsearch(String word){ int cmp, high = outputlist.size(), low = -1, next; // Binary search the array to find the key while (high - low > 1) { next = (high + low) / 2; // all in upper case cmp = word.compareTo((outputlist.get(next)).getWord()); if (cmp == 0) return next; else if (cmp < 0) high = next; else low = next; } return high; } public static void main(String args[]){ // handle input if (args.length == 0){ System.out.println("USAGE: WordCount <filename> [Top # of results to display]\n"); System.exit(1); } String filename = args[0]; int dispnum; try{ dispnum = Integer.parseInt(args[1]); }catch(Exception e){ dispnum = 10; } long start_time = Calendar.getInstance().getTimeInMillis(); WordCount wordcount = new WordCount(); System.out.println("Wordcount: Running..."); // read file char[] input = null; try { input = wordcount.readFile(filename); } catch (Exception e) { // TODO Auto-generated catch block e.printStackTrace(); System.exit(1); } // count all word ArrayList<WordCountNode> result = wordcount.countWords(input); long end_time = Calendar.getInstance().getTimeInMillis(); System.out.println("wordcount: completed " + (end_time - start_time)/1000000 + "." + (end_time - start_time)%1000000 + "(s)"); System.out.println("wordsort: running ..."); start_time = Calendar.getInstance().getTimeInMillis(); Collections.sort(result); end_time = Calendar.getInstance().getTimeInMillis(); System.out.println("wordsort: completed " + (end_time - start_time)/1000000 + "." + (end_time - start_time)%1000000 + "(s)"); Collections.reverse(result); System.out.println("\nresults (TOP "+ dispnum +" from "+ result.size() +"):\n" ); // print out result String str ; for (int i = 0; i < result.size() && i < dispnum; i++){ if(result.get(i).getWord().length() > 15) str = result.get(i).getWord().substring(0, 14); else str = result.get(i).getWord(); System.out.println(str + " - " + result.get(i).getCount()); } } public class WordCountNode implements Comparable{ private String word; private long count; public WordCountNode(long count, String word){ this.count = count; this.word = word; } public String getWord() { return word; } public void setWord(String word) { this.word = word; } public long getCount() { return count; } public void setCount(long count) { this.count = count; } public int compareTo(Object arg0) { // TODO Auto-generated method stub WordCountNode obj = (WordCountNode)arg0; if( count - obj.getCount() < 0) return -1; else if( count - obj.getCount() == 0) return 0; else return 1; } } } Here's my attempt (so far) in C: #include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <string.h> // Read in a file FILE *readFile (char filename[]) { FILE *inputFile; inputFile = fopen (filename, "r"); if (inputFile == NULL) { printf ("File could not be opened.\n"); exit (EXIT_FAILURE); } return inputFile; } // Return number of words in an array int wordCount (FILE *filePointer, char filename[]) {//, char *words[]) { // count words int count = 0; char temp; while ((temp = getc(filePointer)) != EOF) { //printf ("%c", temp); if ((temp == ' ' || temp == '\n') && (temp != '\'')) count++; } count += 1; // counting method uses space AFTER last character in word - the last space // of the last character isn't counted - off by one error // close file fclose (filePointer); return count; } // Print out the frequencies of the 10 most frequent words in the console int main (int argc, char *argv[]) { /* Step 1: Read in file and check for errors */ FILE *filePointer; filePointer = readFile (argv[1]); /* Step 2: Do a word count to prep for array size */ int count = wordCount (filePointer, argv[1]); printf ("Number of words is: %i\n", count); /* Step 3: Create a 2D array to store words in the file */ // open file to reset marker to beginning of file filePointer = fopen (argv[1], "r"); // store words in character array (each element in array = consecutive word) char allWords[count][100]; // 100 is an arbitrary size - max length of word int i,j; char temp; for (i = 0; i < count; i++) { for (j = 0; j < 100; j++) { // labels are used with goto statements, not loops in C temp = getc(filePointer); if ((temp == ' ' || temp == '\n' || temp == EOF) && (temp != '\'') ) { allWords[i][j] = '\0'; break; } else { allWords[i][j] = temp; } printf ("%c", allWords[i][j]); } printf ("\n"); } // close file fclose (filePointer); /* Step 4: Use a simple selection sort algorithm to sort 2D char array */ // PStep 1: Compare two char arrays, and if // (a) c1 > c2, return 2 // (b) c1 == c2, return 1 // (c) c1 < c2, return 0 qsort(allWords, count, sizeof(char[][]), pstrcmp); /* int k = 0, l = 0, m = 0; char currentMax, comparedElement; int max; // the largest element in the current 2D array int elementToSort = 0; // elementToSort determines the element to swap with starting from the left // Outer a iterates through number of swaps needed for (k = 0; k < count - 1; k++) { // times of swaps max = k; // max element set to k // Inner b iterates through successive elements to fish out the largest element for (m = k + 1; m < count - k; m++) { currentMax = allWords[k][l]; comparedElement = allWords[m][l]; // Inner c iterates through successive chars to set the max vars to the largest for (l = 0; (currentMax != '\0' || comparedElement != '\0'); l++) { if (currentMax > comparedElement) break; else if (currentMax < comparedElement) { max = m; currentMax = allWords[m][l]; break; } else if (currentMax == comparedElement) continue; } } // After max (count and string) is determined, perform swap with temp variable char swapTemp[1][20]; int y = 0; do { swapTemp[0][y] = allWords[elementToSort][y]; allWords[elementToSort][y] = allWords[max][y]; allWords[max][y] = swapTemp[0][y]; } while (swapTemp[0][y++] != '\0'); elementToSort++; } */ int a, b; for (a = 0; a < count; a++) { for (b = 0; (temp = allWords[a][b]) != '\0'; b++) { printf ("%c", temp); } printf ("\n"); } // Copy rows to different array and print results /* char arrayCopy [count][20]; int ac, ad; char tempa; for (ac = 0; ac < count; ac++) { for (ad = 0; (tempa = allWords[ac][ad]) != '\0'; ad++) { arrayCopy[ac][ad] = tempa; printf("%c", arrayCopy[ac][ad]); } printf("\n"); } */ /* Step 5: Create two additional arrays: (a) One in which each element contains unique words from char array (b) One which holds the count for the corresponding word in the other array */ /* Step 6: Sort the count array in decreasing order, and print the corresponding array element as well as word count in the console */ return 0; } // Perform housekeeping tasks like freeing up memory and closing file I'm really stuck on the selection sort algorithm. I'm currently using 2D arrays to represent strings, and that worked out fine, but when it came to sorting, using three level nested loops didn't seem to work, I tried to use qsort instead, but I don't fully understand that function as well. Constructive feedback and criticism greatly welcome (...and needed)!

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ASP.NET MVC 3 Hosting :: New Features in ASP.NET MVC 3

- by mbridge

Razor View Engine The Razor view engine is a new view engine option for ASP.NET MVC that supports the Razor templating syntax. The Razor syntax is a streamlined approach to HTML templating designed with the goal of being a code driven minimalist templating approach that builds on existing C#, VB.NET and HTML knowledge. The result of this approach is that Razor views are very lean and do not contain unnecessary constructs that get in the way of you and your code. ASP.NET MVC 3 Preview 1 only supports C# Razor views which use the .cshtml file extension. VB.NET support will be enabled in later releases of ASP.NET MVC 3. For more information and examples, see Introducing “Razor” – a new view engine for ASP.NET on Scott Guthrie’s blog. Dynamic View and ViewModel Properties A new dynamic View property is available in views, which provides access to the ViewData object using a simpler syntax. For example, imagine two items are added to the ViewData dictionary in the Index controller action using code like the following: public ActionResult Index() { ViewData["Title"] = "The Title"; ViewData["Message"] = "Hello World!"; } Those properties can be accessed in the Index view using code like this: <h2>View.Title</h2> <p>View.Message</p> There is also a new dynamic ViewModel property in the Controller class that lets you add items to the ViewData dictionary using a simpler syntax. Using the previous controller example, the two values added to the ViewData dictionary can be rewritten using the following code: public ActionResult Index() { ViewModel.Title = "The Title"; ViewModel.Message = "Hello World!"; } “Add View” Dialog Box Supports Multiple View Engines The Add View dialog box in Visual Studio includes extensibility hooks that allow it to support multiple view engines, as shown in the following figure: Service Location and Dependency Injection Support ASP.NET MVC 3 introduces improved support for applying Dependency Injection (DI) via Inversion of Control (IoC) containers. ASP.NET MVC 3 Preview 1 provides the following hooks for locating services and injecting dependencies: - Creating controller factories. - Creating controllers and setting dependencies. - Setting dependencies on view pages for both the Web Form view engine and the Razor view engine (for types that derive from ViewPage, ViewUserControl, ViewMasterPage, WebViewPage). - Setting dependencies on action filters. Using a Dependency Injection container is not required in order for ASP.NET MVC 3 to function properly. Global Filters ASP.NET MVC 3 allows you to register filters that apply globally to all controller action methods. Adding a filter to the global filters collection ensures that the filter runs for all controller requests. To register an action filter globally, you can make the following call in the Application_Start method in the Global.asax file: GlobalFilters.Filters.Add(new MyActionFilter()); The source of global action filters is abstracted by the new IFilterProvider interface, which can be registered manually or by using Dependency Injection. This allows you to provide your own source of action filters and choose at run time whether to apply a filter to an action in a particular request. New JsonValueProviderFactory Class The new JsonValueProviderFactory class allows action methods to receive JSON-encoded data and model-bind it to an action-method parameter. This is useful in scenarios such as client templating. Client templates enable you to format and display a single data item or set of data items by using a fragment of HTML. ASP.NET MVC 3 lets you connect client templates easily with an action method that both returns and receives JSON data. Support for .NET Framework 4 Validation Attributes and IvalidatableObject The ValidationAttribute class was improved in the .NET Framework 4 to enable richer support for validation. When you write a custom validation attribute, you can use a new IsValid overload that provides a ValidationContext instance. This instance provides information about the current validation context, such as what object is being validated. This change enables scenarios such as validating the current value based on another property of the model. The following example shows a sample custom attribute that ensures that the value of PropertyOne is always larger than the value of PropertyTwo: public class CompareValidationAttribute : ValidationAttribute { protected override ValidationResult IsValid(object value, ValidationContext validationContext) { var model = validationContext.ObjectInstance as SomeModel; if (model.PropertyOne > model.PropertyTwo) { return ValidationResult.Success; } return new ValidationResult("PropertyOne must be larger than PropertyTwo"); } } Validation in ASP.NET MVC also supports the .NET Framework 4 IValidatableObject interface. This interface allows your model to perform model-level validation, as in the following example: public class SomeModel : IValidatableObject { public int PropertyOne { get; set; } public int PropertyTwo { get; set; } public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) { if (PropertyOne <= PropertyTwo) { yield return new ValidationResult( "PropertyOne must be larger than PropertyTwo"); } } } New IClientValidatable Interface The new IClientValidatable interface allows the validation framework to discover at run time whether a validator has support for client validation. This interface is designed to be independent of the underlying implementation; therefore, where you implement the interface depends on the validation framework in use. For example, for the default data annotations-based validator, the interface would be applied on the validation attribute. Support for .NET Framework 4 Metadata Attributes ASP.NET MVC 3 now supports .NET Framework 4 metadata attributes such as DisplayAttribute. New IMetadataAware Interface The new IMetadataAware interface allows you to write attributes that simplify how you can contribute to the ModelMetadata creation process. Before this interface was available, you needed to write a custom metadata provider in order to have an attribute provide extra metadata. This interface is consumed by the AssociatedMetadataProvider class, so support for the IMetadataAware interface is automatically inherited by all classes that derive from that class (notably, the DataAnnotationsModelMetadataProvider class). New Action Result Types In ASP.NET MVC 3, the Controller class includes two new action result types and corresponding helper methods. HttpNotFoundResult Action The new HttpNotFoundResult action result is used to indicate that a resource requested by the current URL was not found. The status code is 404. This class derives from HttpStatusCodeResult. The Controller class includes an HttpNotFound method that returns an instance of this action result type, as shown in the following example: public ActionResult List(int id) { if (id < 0) { return HttpNotFound(); } return View(); } HttpStatusCodeResult Action The new HttpStatusCodeResult action result is used to set the response status code and description. Permanent Redirect The HttpRedirectResult class has a new Boolean Permanent property that is used to indicate whether a permanent redirect should occur. A permanent redirect uses the HTTP 301 status code. Corresponding to this change, the Controller class now has several methods for performing permanent redirects: - RedirectPermanent - RedirectToRoutePermanent - RedirectToActionPermanent These methods return an instance of HttpRedirectResult with the Permanent property set to true. Breaking Changes The order of execution for exception filters has changed for exception filters that have the same Order value. In ASP.NET MVC 2 and earlier, exception filters on the controller with the same Order as those on an action method were executed before the exception filters on the action method. This would typically be the case when exception filters were applied without a specified order Order value. In MVC 3, this order has been reversed in order to allow the most specific exception handler to execute first. As in earlier versions, if the Order property is explicitly specified, the filters are run in the specified order. Known Issues When you are editing a Razor view (CSHTML file), the Go To Controller menu item in Visual Studio will not be available, and there are no code snippets.

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.NET WebAPI Serialization k_BackingField Nastiness

- by Micah

When i serialize the following: [Serializable] public class Error { public string Status { get; set; } public string Message { get; set; } public string ErrorReferenceCode { get; set; } public List<FriendlyError> Errors { get; set; } } I get this disgusting mess: <ErrorRootOfstring xmlns:i="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.datacontract.org/2004/07/Printmee.Api"> <_x003C_Errors_x003E_k__BackingField> An exception has occurred. Please contact printmee support </_x003C_Errors_x003E_k__BackingField> <_x003C_LookupCode_x003E_k__BackingField>988232ec-6bc9-48f3-8116-7ff7c71302dd</_x003C_LookupCode_x003E_k__BackingField> </ErrorRootOfstring> What gives? How can i make this pretty? JSON responses also contain the k_BackingField

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Linq: Converting flat structure to hierarchical

- by Stefan Steinegger

What is the easiest and somewhat efficient way to convert a flat structure: object[][] rawData = new object[][] { { "A1", "B1", "C1" }, { "A1", "B1", "C2" }, { "A2", "B2", "C3" }, { "A2", "B2", "C4" } // .. more }; into a hierarchical structure: class X { public X () { Cs = new List<string>(); } public string A { get; set; } public string B { get; set; } public List<string> Cs { get; private set; } } the result should look like this // pseudo code which describes structure: result = { new X() { A = "A1", B = "B1", Cs = { "C1", "C2" } }, new X() { A = "A2", B = "B2", Cs = { "C3", "C4" } } } Preferably using Linq extension methods. Target class X could be changed (eg. a public setter for the List), only if not possible / useful as it is now.

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Having trouble binding a ksoap object to an ArrayList in Android

- by Maskau

I'm working on an app that calls a web service, then the webservice returns an array list. My problem is I am having trouble getting the data into the ArrayList and then displaying in a ListView. Any ideas what I am doing wrong? I know for a fact the web service returns an ArrayList. Everything seems to be working fine, just no data in the ListView or the ArrayList.....Thanks in advance! EDIT: So I added more code to the catch block of run() and now it's returning "org.ksoap2.serialization.SoapObject".....no more no less....and I am even more confused now... package com.maskau; import java.util.ArrayList; import org.ksoap2.SoapEnvelope; import org.ksoap2.serialization.PropertyInfo; import org.ksoap2.serialization.SoapObject; import org.ksoap2.serialization.SoapSerializationEnvelope; import org.ksoap2.transport.AndroidHttpTransport; import android.app.*; import android.os.*; import android.widget.ArrayAdapter; import android.widget.Button; import android.widget.EditText; import android.widget.ListView; import android.widget.TextView; import android.view.View; import android.view.View.OnClickListener; public class Home extends Activity implements Runnable{ /** Called when the activity is first created. */ public static final String SOAP_ACTION = "http://bb.mcrcog.com/GetArtist"; public static final String METHOD_NAME = "GetArtist"; public static final String NAMESPACE = "http://bb.mcrcog.com"; public static final String URL = "http://bb.mcrcog.com/karaoke/service.asmx"; String wt; public static ProgressDialog pd; TextView text1; ListView lv; static EditText myEditText; static Button but; private ArrayList<String> Artist_Result = new ArrayList<String>(); @Override public void onCreate(Bundle icicle) { super.onCreate(icicle); setContentView(R.layout.main); myEditText = (EditText)findViewById(R.id.myEditText); text1 = (TextView)findViewById(R.id.text1); lv = (ListView)findViewById(R.id.lv); but = (Button)findViewById(R.id.but); but.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { wt = ("Searching for " + myEditText.getText().toString()); text1.setText(""); pd = ProgressDialog.show(Home.this, "Working...", wt , true, false); Thread thread = new Thread(Home.this); thread.start(); } } ); } public void run() { try { SoapObject request = new SoapObject(NAMESPACE, METHOD_NAME); PropertyInfo pi = new PropertyInfo(); pi.setName("ArtistQuery"); pi.setValue(Home.myEditText.getText().toString()); request.addProperty(pi); SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11); envelope.dotNet = true; envelope.setOutputSoapObject(request); AndroidHttpTransport at = new AndroidHttpTransport(URL); at.call(SOAP_ACTION, envelope); java.util.Vector<Object> rs = (java.util.Vector<Object>)envelope.getResponse(); if (rs != null) { for (Object cs : rs) { Artist_Result.add(cs.toString()); } } } catch (Exception e) { // Added this line, throws "org.ksoap2.serialization.SoapObject" when run Artist_Result.add(e.getMessage()); } handler.sendEmptyMessage(0); } private Handler handler = new Handler() { @Override public void handleMessage(Message msg) { ArrayAdapter<String> aa; aa = new ArrayAdapter<String>(Home.this, android.R.layout.simple_list_item_1, Artist_Result); lv.setAdapter(aa); try { if (Artist_Result.isEmpty()) { text1.setText("No Results"); } else { text1.setText("Complete"); myEditText.setText("Search Artist"); } } catch(Exception e) { text1.setText(e.getMessage()); } aa.notifyDataSetChanged(); pd.dismiss(); } }; }

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C# 4: The Curious ConcurrentDictionary

- by James Michael Hare

In my previous post (here) I did a comparison of the new ConcurrentQueue versus the old standard of a System.Collections.Generic Queue with simple locking. The results were exactly what I would have hoped, that the ConcurrentQueue was faster with multi-threading for most all situations. In addition, concurrent collections have the added benefit that you can enumerate them even if they're being modified. So I set out to see what the improvements would be for the ConcurrentDictionary, would it have the same performance benefits as the ConcurrentQueue did? Well, after running some tests and multiple tweaks and tunes, I have good and bad news. But first, let's look at the tests. Obviously there's many things we can do with a dictionary. One of the most notable uses, of course, in a multi-threaded environment is for a small, local in-memory cache. So I set about to do a very simple simulation of a cache where I would create a test class that I'll just call an Accessor. This accessor will attempt to look up a key in the dictionary, and if the key exists, it stops (i.e. a cache "hit"). However, if the lookup fails, it will then try to add the key and value to the dictionary (i.e. a cache "miss"). So here's the Accessor that will run the tests: 1: internal class Accessor 2: { 3: public int Hits { get; set; } 4: public int Misses { get; set; } 5: public Func<int, string> GetDelegate { get; set; } 6: public Action<int, string> AddDelegate { get; set; } 7: public int Iterations { get; set; } 8: public int MaxRange { get; set; } 9: public int Seed { get; set; } 10: 11: public void Access() 12: { 13: var randomGenerator = new Random(Seed); 14: 15: for (int i=0; i<Iterations; i++) 16: { 17: // give a wide spread so will have some duplicates and some unique 18: var target = randomGenerator.Next(1, MaxRange); 19: 20: // attempt to grab the item from the cache 21: var result = GetDelegate(target); 22: 23: // if the item doesn't exist, add it 24: if(result == null) 25: { 26: AddDelegate(target, target.ToString()); 27: Misses++; 28: } 29: else 30: { 31: Hits++; 32: } 33: } 34: } 35: } Note that so I could test different implementations, I defined a GetDelegate and AddDelegate that will call the appropriate dictionary methods to add or retrieve items in the cache using various techniques. So let's examine the three techniques I decided to test: Dictionary with mutex - Just your standard generic Dictionary with a simple lock construct on an internal object. Dictionary with ReaderWriterLockSlim - Same Dictionary, but now using a lock designed to let multiple readers access simultaneously and then locked when a writer needs access. ConcurrentDictionary - The new ConcurrentDictionary from System.Collections.Concurrent that is supposed to be optimized to allow multiple threads to access safely. So the approach to each of these is also fairly straight-forward. Let's look at the GetDelegate and AddDelegate implementations for the Dictionary with mutex lock: 1: var addDelegate = (key,val) => 2: { 3: lock (_mutex) 4: { 5: _dictionary[key] = val; 6: } 7: }; 8: var getDelegate = (key) => 9: { 10: lock (_mutex) 11: { 12: string val; 13: return _dictionary.TryGetValue(key, out val) ? val : null; 14: } 15: }; Nothing new or fancy here, just your basic lock on a private object and then query/insert into the Dictionary. Now, for the Dictionary with ReadWriteLockSlim it's a little more complex: 1: var addDelegate = (key,val) => 2: { 3: _readerWriterLock.EnterWriteLock(); 4: _dictionary[key] = val; 5: _readerWriterLock.ExitWriteLock(); 6: }; 7: var getDelegate = (key) => 8: { 9: string val; 10: _readerWriterLock.EnterReadLock(); 11: if(!_dictionary.TryGetValue(key, out val)) 12: { 13: val = null; 14: } 15: _readerWriterLock.ExitReadLock(); 16: return val; 17: }; And finally, the ConcurrentDictionary, which since it does all it's own concurrency control, is remarkably elegant and simple: 1: var addDelegate = (key,val) => 2: { 3: _concurrentDictionary[key] = val; 4: }; 5: var getDelegate = (key) => 6: { 7: string s; 8: return _concurrentDictionary.TryGetValue(key, out s) ? s : null; 9: }; Then, I set up a test harness that would simply ask the user for the number of concurrent Accessors to attempt to Access the cache (as specified in Accessor.Access() above) and then let them fly and see how long it took them all to complete. Each of these tests was run with 10,000,000 cache accesses divided among the available Accessor instances. All times are in milliseconds. 1: Dictionary with Mutex Locking 2: --------------------------------------------------- 3: Accessors Mostly Misses Mostly Hits 4: 1 7916 3285 5: 10 8293 3481 6: 100 8799 3532 7: 1000 8815 3584 8: 9: 10: Dictionary with ReaderWriterLockSlim Locking 11: --------------------------------------------------- 12: Accessors Mostly Misses Mostly Hits 13: 1 8445 3624 14: 10 11002 4119 15: 100 11076 3992 16: 1000 14794 4861 17: 18: 19: Concurrent Dictionary 20: --------------------------------------------------- 21: Accessors Mostly Misses Mostly Hits 22: 1 17443 3726 23: 10 14181 1897 24: 100 15141 1994 25: 1000 17209 2128 The first test I did across the board is the Mostly Misses category. The mostly misses (more adds because data requested was not in the dictionary) shows an interesting trend. In both cases the Dictionary with the simple mutex lock is much faster, and the ConcurrentDictionary is the slowest solution. But this got me thinking, and a little research seemed to confirm it, maybe the ConcurrentDictionary is more optimized to concurrent "gets" than "adds". So since the ratio of misses to hits were 2 to 1, I decided to reverse that and see the results. So I tweaked the data so that the number of keys were much smaller than the number of iterations to give me about a 2 to 1 ration of hits to misses (twice as likely to already find the item in the cache than to need to add it). And yes, indeed here we see that the ConcurrentDictionary is indeed faster than the standard Dictionary here. I have a strong feeling that as the ration of hits-to-misses gets higher and higher these number gets even better as well. This makes sense since the ConcurrentDictionary is read-optimized. Also note that I tried the tests with capacity and concurrency hints on the ConcurrentDictionary but saw very little improvement, I think this is largely because on the 10,000,000 hit test it quickly ramped up to the correct capacity and concurrency and thus the impact was limited to the first few milliseconds of the run. So what does this tell us? Well, as in all things, ConcurrentDictionary is not a panacea. It won't solve all your woes and it shouldn't be the only Dictionary you ever use. So when should we use each? Use System.Collections.Generic.Dictionary when: You need a single-threaded Dictionary (no locking needed). You need a multi-threaded Dictionary that is loaded only once at creation and never modified (no locking needed). You need a multi-threaded Dictionary to store items where writes are far more prevalent than reads (locking needed). And use System.Collections.Concurrent.ConcurrentDictionary when: You need a multi-threaded Dictionary where the writes are far more prevalent than reads. You need to be able to iterate over the collection without locking it even if its being modified. Both Dictionaries have their strong suits, I have a feeling this is just one where you need to know from design what you hope to use it for and make your decision based on that criteria.

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Java: immutability, overuse of stack -- better data structure?

- by HH

I overused hashSets but it was slow, then changed to Stacks, speed boost-up. Poly's reply uses Collections.emptyList() as immutable list, cutting out excess null-checkers. No Collections.emptyStack(). Combining the words stack and immutability, from the last experiences, gets "immutable stack" (probably not related to functional prog). Java Api 5 for list interface shows that Stack is an implementing class for list and arraylist, here. The java.coccurrent pkg does not have any immutable Stack data structure. The first hinted of misusing stack. The lack of immutabily in the last and poly's book recommendation leads way to list. Something very primitive, fast, no extra layers, with methods like emptyThing(). Overuse of stack and where I use it DataFile.java: public Stack<DataFile> files; FileObject.java: public Stack<String> printViews = new Stack<String>(); FileObject.java:// private static Stack<Object> getFormat(File f){return (new Format(f)).getFormat();} Format.java: private Stack<Object> getLine(File[] fs,String s){return wF;} Format.java: private Stack<Object> getFormat(){return format;} Positions.java: public static Stack<Integer[]> getPrintPoss(String s,File f,Integer maxViewPerF) Positions.java: Stack<File> possPrint = new Stack<File>(); Positions.java: Stack<Integer> positions=new Stack<Integer>(); Record.java: private String getFormatLine(Stack<Object> st) Record.java: Stack<String> lines=new Stack<String>(); SearchToUser.java: public static final Stack<File> allFiles = findf.getFs(); SearchToUser.java: public static final Stack<File> allDirs = findf.getDs(); SearchToUser.java: private Stack<Integer[]> positionsPrint=new Stack<Integer[]>(); SearchToUser.java: public Stack<String> getSearchResults(String s, Integer countPerFile, Integer resCount) SearchToUser.java: Stack<File> filesToS=Fs2Word.getFs2W(s,50); SearchToUser.java: Stack<String> rs=new Stack<String>(); View.java: public Stack<Integer[]> poss = new Stack<Integer[4]>(); View.java: public static Stack<String> getPrintViewsFileWise(String s,Object[] df,Integer maxViewsPerF) View.java: Stack<String> substrings = new Stack<String>(); View.java: private Stack<String> printViews=new Stack<String>(); View.java: MatchView(Stack<Integer> pss,File f,Integer maxViews) View.java: Stack<String> formatFile; View.java: private Stack<Search> files; View.java: private Stack<File> matchingFiles; View.java: private Stack<String> matchViews; View.java: private Stack<String> searchMatches; View.java: private Stack<String> getSearchResults(Integer numbResults) Easier with List: AllDirs and AllFs, now looping with push, but list has more pow. methods such as addAll [OLD] From Stack to some immutable data structure How to get immutable Stack data structure? Can I box it with list? Should I switch my current implementatios from stacks to Lists to get immutable? Which immutable data structure is Very fast with about similar exec time as Stack? No immutability to Stack with Final import java.io.*; import java.util.*; public class TestStack{ public static void main(String[] args) { final Stack<Integer> test = new Stack<Integer>(); Stack<Integer> test2 = new Stack<Integer>(); test.push(37707); test2.push(80437707); //WHY is there not an error to remove an elment // from FINAL stack? System.out.println(test.pop()); System.out.println(test2.pop()); } }

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How can I eager-load a child collection mapped to a non-primary key in NHibernate 2.1.2?

- by David Rubin

Hi, I have two objects with a many-to-many relationship between them, as follows: public class LeftHandSide { public LeftHandSide() { Name = String.Empty; Rights = new HashSet<RightHandSide>(); } public int Id { get; set; } public string Name { get; set; } public ICollection<RightHandSide> Rights { get; set; } } public class RightHandSide { public RightHandSide() { OtherProp = String.Empty; Lefts = new HashSet<LeftHandSide>(); } public int Id { get; set; } public string OtherProp { get; set; } public ICollection<LeftHandSide> Lefts { get; set; } } and I'm using a legacy database, so my mappings look like: Notice that LeftHandSide and RightHandSide are associated by a different column than RightHandSide's primary key. <class name="LeftHandSide" table="[dbo].[lefts]" lazy="false"> <id name="Id" column="ID" unsaved-value="0"> <generator class="identity" /> </id> <property name="Name" not-null="true" /> <set name="Rights" table="[dbo].[lefts2rights]"> <key column="leftId" />  <many-to-many class="RightHandSide" column="rightProp" property-ref="OtherProp" /> </set> </class> <class name="RightHandSide" table="[dbo].[rights]" lazy="false"> <id name="Id" column="id" unsaved-value="0"> <generator class="identity" /> </id> <property name="OtherProp" column="otherProp" /> <set name="Lefts" table="[dbo].[lefts2rights]">  <key column="rightProp" property-ref="OtherProp" /> <many-to-many class="LeftHandSide" column="leftId" /> </set> </class> The problem comes when I go to do a query: LeftHandSide lhs = _session.CreateCriteria<LeftHandSide>() .Add(Expression.IdEq(13)) .UniqueResult<LeftHandSide>(); works just fine. But LeftHandSide lhs = _session.CreateCriteria<LeftHandSide>() .Add(Expression.IdEq(13)) .SetFetchMode("Rights", FetchMode.Join) .UniqueResult<LeftHandSide>(); throws an exception (see below). Interestingly, RightHandSide rhs = _session.CreateCriteria<RightHandSide>() .Add(Expression.IdEq(127)) .SetFetchMode("Lefts", FetchMode.Join) .UniqueResult<RightHandSide>(); seems to be perfectly fine as well. NHibernate.Exceptions.GenericADOException Message: Error performing LoadByUniqueKey[SQL: SQL not available] Source: NHibernate StackTrace: c:\opt\nhibernate\2.1.2\source\src\NHibernate\Type\EntityType.cs(563,0): at NHibernate.Type.EntityType.LoadByUniqueKey(String entityName, String uniqueKeyPropertyName, Object key, ISessionImplementor session) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Type\EntityType.cs(428,0): at NHibernate.Type.EntityType.ResolveIdentifier(Object value, ISessionImplementor session, Object owner) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Type\EntityType.cs(300,0): at NHibernate.Type.EntityType.NullSafeGet(IDataReader rs, String[] names, ISessionImplementor session, Object owner) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Persister\Collection\AbstractCollectionPersister.cs(695,0): at NHibernate.Persister.Collection.AbstractCollectionPersister.ReadElement(IDataReader rs, Object owner, String[] aliases, ISessionImplementor session) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Collection\Generic\PersistentGenericSet.cs(54,0): at NHibernate.Collection.Generic.PersistentGenericSet`1.ReadFrom(IDataReader rs, ICollectionPersister role, ICollectionAliases descriptor, Object owner) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(706,0): at NHibernate.Loader.Loader.ReadCollectionElement(Object optionalOwner, Object optionalKey, ICollectionPersister persister, ICollectionAliases descriptor, IDataReader rs, ISessionImplementor session) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(385,0): at NHibernate.Loader.Loader.ReadCollectionElements(Object[] row, IDataReader resultSet, ISessionImplementor session) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(326,0): at NHibernate.Loader.Loader.GetRowFromResultSet(IDataReader resultSet, ISessionImplementor session, QueryParameters queryParameters, LockMode[] lockModeArray, EntityKey optionalObjectKey, IList hydratedObjects, EntityKey[] keys, Boolean returnProxies) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(453,0): at NHibernate.Loader.Loader.DoQuery(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(236,0): at NHibernate.Loader.Loader.DoQueryAndInitializeNonLazyCollections(ISessionImplementor session, QueryParameters queryParameters, Boolean returnProxies) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(1649,0): at NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(1568,0): at NHibernate.Loader.Loader.ListIgnoreQueryCache(ISessionImplementor session, QueryParameters queryParameters) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Loader.cs(1562,0): at NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet`1 querySpaces, IType[] resultTypes) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Loader\Criteria\CriteriaLoader.cs(73,0): at NHibernate.Loader.Criteria.CriteriaLoader.List(ISessionImplementor session) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Impl\SessionImpl.cs(1936,0): at NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria, IList results) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Impl\CriteriaImpl.cs(246,0): at NHibernate.Impl.CriteriaImpl.List(IList results) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Impl\CriteriaImpl.cs(237,0): at NHibernate.Impl.CriteriaImpl.List() c:\opt\nhibernate\2.1.2\source\src\NHibernate\Impl\CriteriaImpl.cs(398,0): at NHibernate.Impl.CriteriaImpl.UniqueResult() c:\opt\nhibernate\2.1.2\source\src\NHibernate\Impl\CriteriaImpl.cs(263,0): at NHibernate.Impl.CriteriaImpl.UniqueResult[T]() D:\proj\CMS3\branches\nh_auth\DomainModel2Tests\Authorization\TempTests.cs(46,0): at CMS.DomainModel.Authorization.TempTests.Test1() Inner Exception System.Collections.Generic.KeyNotFoundException Message: The given key was not present in the dictionary. Source: mscorlib StackTrace: at System.ThrowHelper.ThrowKeyNotFoundException() at System.Collections.Generic.Dictionary`2.get_Item(TKey key) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Persister\Entity\AbstractEntityPersister.cs(2047,0): at NHibernate.Persister.Entity.AbstractEntityPersister.GetAppropriateUniqueKeyLoader(String propertyName, IDictionary`2 enabledFilters) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Persister\Entity\AbstractEntityPersister.cs(2037,0): at NHibernate.Persister.Entity.AbstractEntityPersister.LoadByUniqueKey(String propertyName, Object uniqueKey, ISessionImplementor session) c:\opt\nhibernate\2.1.2\source\src\NHibernate\Type\EntityType.cs(552,0): at NHibernate.Type.EntityType.LoadByUniqueKey(String entityName, String uniqueKeyPropertyName, Object key, ISessionImplementor session) I'm using NHibernate 2.1.2 and I've been debugging into the NHibernate source, but I'm coming up empty. Any suggestions? Thanks so much!

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JUnit Parameterized Runner and mvn Surefire Report integration

- by fraido

I'm using the Junit Parameterized Runner and the Maven Plugin Surefire Report to generate detailed reports during the mvn site phase. I've something like this @RunWith(Parameterized.class) public class MyTest { private String string1; private String string2; @Parameterized.Parameters public static Collection params() { return Arrays.asList(new String[][] { { "1", "2"}, { "3", "4"}, { "5", "6"} }); } public MyTest(String string1, String string2) { this.string1 = string1; this.string2 = string2; } @Test public void myTestMethod() { ... } @Test public void myOtherTestMethod() { ... } The report shows something like myTestMethod[0] 0.018 myTestMethod[1] 0.009 myTestMethod[2] 0.009 ... myOtherTestMethod[0] 0.018 myOtherTestMethod[1] 0.009 myOtherTestMethod[2] 0.009 ... Is there a way to display something else rather than the iteration number [0]..[1]..etc.. The constructor parameters would be a much better information. For example myTestMethod["1", "2"] 0.018 ...

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Reflect on an ExpandoObject

- by Water Cooler v2

I have written a nifty function that will accept a system.object, reflect on its properties and serialize the object into a JSON string. It looks like this: public class JSONSerializer { public string Serialize(object obj) Now, I want to be able to do this to serialize a dynamic/ExpandoObject, but because my serializer uses reflection, it isn't able to do it. What's the workaround? public class Test { public dynamic MakeDynamicCat() { dynamic newCat = new ExpandoObject(); newCat.Name = "Polly"; newCat.Pedigree = new ExpandoObject(); newCat.Pedigree.Breed = "Whatever"; return newCat; } public void SerializeCat() { new JSONSerializer().Serialize(MakeDynamicCat()); } }

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MvcExtensions – Bootstrapping

- by kazimanzurrashid

When you create a new ASP.NET MVC application you will find that the global.asax contains the following lines: namespace MvcApplication1 { // Note: For instructions on enabling IIS6 or IIS7 classic mode, // visit http://go.microsoft.com/?LinkId=9394801 public class MvcApplication : System.Web.HttpApplication { public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute( "Default", // Route name "{controller}/{action}/{id}", // URL with parameters new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults ); } protected void Application_Start() { AreaRegistration.RegisterAllAreas(); RegisterRoutes(RouteTable.Routes); } } } As the application grows, there are quite a lot of plumbing code gets into the global.asax which quickly becomes a design smell. Lets take a quick look at the code of one of the open source project that I recently visited: public static void RegisterRoutes(RouteCollection routes) { routes.IgnoreRoute("{resource}.axd/{*pathInfo}"); routes.MapRoute("Default","{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = "" }); } protected override void OnApplicationStarted() { Error += OnError; EndRequest += OnEndRequest; var settings = new SparkSettings() .AddNamespace("System") .AddNamespace("System.Collections.Generic") .AddNamespace("System.Web.Mvc") .AddNamespace("System.Web.Mvc.Html") .AddNamespace("MvcContrib.FluentHtml") .AddNamespace("********") .AddNamespace("********.Web") .SetPageBaseType("ApplicationViewPage") .SetAutomaticEncoding(true); #if DEBUG settings.SetDebug(true); #endif var viewFactory = new SparkViewFactory(settings); ViewEngines.Engines.Add(viewFactory); #if !DEBUG PrecompileViews(viewFactory); #endif RegisterAllControllersIn("********.Web"); log4net.Config.XmlConfigurator.Configure(); RegisterRoutes(RouteTable.Routes); Factory.Load(new Components.WebDependencies()); ModelBinders.Binders.DefaultBinder = new Binders.GenericBinderResolver(Factory.TryGet<IModelBinder>); ValidatorConfiguration.Initialize("********"); HtmlValidationExtensions.Initialize(ValidatorConfiguration.Rules); } private void OnEndRequest(object sender, System.EventArgs e) { if (((HttpApplication)sender).Context.Handler is MvcHandler) { CreateKernel().Get<ISessionSource>().Close(); } } private void OnError(object sender, System.EventArgs e) { CreateKernel().Get<ISessionSource>().Close(); } protected override IKernel CreateKernel() { return Factory.Kernel; } private static void PrecompileViews(SparkViewFactory viewFactory) { var batch = new SparkBatchDescriptor(); batch.For<HomeController>().For<ManageController>(); viewFactory.Precompile(batch); } As you can see there are quite a few of things going on in the above code, Registering the ViewEngine, Compiling the Views, Registering the Routes/Controllers/Model Binders, Settings up Logger, Validations and as you can imagine the more it becomes complex the more things will get added in the application start. One of the goal of the MVCExtensions is to reduce the above design smell. Instead of writing all the plumbing code in the application start, it contains BootstrapperTask to register individual services. Out of the box, it contains BootstrapperTask to register Controllers, Controller Factory, Action Invoker, Action Filters, Model Binders, Model Metadata/Validation Providers, ValueProvideraFactory, ViewEngines etc and it is intelligent enough to automatically detect the above types and register into the ASP.NET MVC Framework. Other than the built-in tasks you can create your own custom task which will be automatically executed when the application starts. When the BootstrapperTasks are in action you will find the global.asax pretty much clean like the following: public class MvcApplication : UnityMvcApplication { public void ErrorLog_Filtering(object sender, ExceptionFilterEventArgs e) { Check.Argument.IsNotNull(e, "e"); HttpException exception = e.Exception.GetBaseException() as HttpException; if ((exception != null) && (exception.GetHttpCode() == (int)HttpStatusCode.NotFound)) { e.Dismiss(); } } } The above code is taken from my another open source project Shrinkr, as you can see the global.asax is longer cluttered with any plumbing code. One special thing you have noticed that it is inherited from the UnityMvcApplication rather than regular HttpApplication. There are separate version of this class for each IoC Container like NinjectMvcApplication, StructureMapMvcApplication etc. Other than executing the built-in tasks, the Shrinkr also has few custom tasks which gets executed when the application starts. For example, when the application starts, we want to ensure that the default users (which is specified in the web.config) are created. The following is the custom task that is used to create those default users: public class CreateDefaultUsers : BootstrapperTask { protected override TaskContinuation ExecuteCore(IServiceLocator serviceLocator) { IUserRepository userRepository = serviceLocator.GetInstance<IUserRepository>(); IUnitOfWork unitOfWork = serviceLocator.GetInstance<IUnitOfWork>(); IEnumerable<User> users = serviceLocator.GetInstance<Settings>().DefaultUsers; bool shouldCommit = false; foreach (User user in users) { if (userRepository.GetByName(user.Name) == null) { user.AllowApiAccess(ApiSetting.InfiniteLimit); userRepository.Add(user); shouldCommit = true; } } if (shouldCommit) { unitOfWork.Commit(); } return TaskContinuation.Continue; } } There are several other Tasks in the Shrinkr that we are also using which you will find in that project. To create a custom bootstrapping task you have create a new class which either implements the IBootstrapperTask interface or inherits from the abstract BootstrapperTask class, I would recommend to start with the BootstrapperTask as it already has the required code that you have to write in case if you choose the IBootstrapperTask interface. As you can see in the above code we are overriding the ExecuteCore to create the default users, the MVCExtensions is responsible for populating the ServiceLocator prior calling this method and in this method we are using the service locator to get the dependencies that are required to create the users (I will cover the custom dependencies registration in the next post). Once the users are created, we are returning a special enum, TaskContinuation as the return value, the TaskContinuation can have three values Continue (default), Skip and Break. The reason behind of having this enum is, in some special cases you might want to skip the next task in the chain or break the complete chain depending upon the currently running task, in those cases you will use the other two values instead of the Continue. The last thing I want to cover in the bootstrapping task is the Order. By default all the built-in tasks as well as newly created task order is set to the DefaultOrder(a static property), in some special cases you might want to execute it before/after all the other tasks, in those cases you will assign the Order in the Task constructor. For Example, in Shrinkr, we want to run few background services when the all the tasks are executed, so we assigned the order as DefaultOrder + 1. Here is the code of that Task: public class ConfigureBackgroundServices : BootstrapperTask { private IEnumerable<IBackgroundService> backgroundServices; public ConfigureBackgroundServices() { Order = DefaultOrder + 1; } protected override TaskContinuation ExecuteCore(IServiceLocator serviceLocator) { backgroundServices = serviceLocator.GetAllInstances<IBackgroundService>().ToList(); backgroundServices.Each(service => service.Start()); return TaskContinuation.Continue; } protected override void DisposeCore() { backgroundServices.Each(service => service.Stop()); } } That’s it for today, in the next post I will cover the custom service registration, so stay tuned.

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Validation in Silverlight

- by Timmy Kokke

Getting started with the basics Validation in Silverlight can get very complex pretty easy. The DataGrid control is the only control that does data validation automatically, but often you want to validate your own entry form. Values a user may enter in this form can be restricted by the customer and have to fit an exact fit to a list of requirements or you just want to prevent problems when saving the data to the database. Showing a message to the user when a value is entered is pretty straight forward as I’ll show you in the following example. This (default) Silverlight textbox is data-bound to a simple data class. It has to be bound in “Two-way” mode to be sure the source value is updated when the target value changes. The INotifyPropertyChanged interface must be implemented by the data class to get the notification system to work. When the property changes a simple check is performed and when it doesn’t match some criteria an ValidationException is thrown. The ValidatesOnExceptions binding attribute is set to True to tell the textbox it should handle the thrown ValidationException. Let’s have a look at some code now. The xaml should contain something like below. The most important part is inside the binding. In this case the Text property is bound to the “Name” property in TwoWay mode. It is also told to validate on exceptions. This property is false by default. <StackPanel Orientation="Horizontal"> <TextBox Width="150" x:Name="Name" Text="{Binding Path=Name, Mode=TwoWay, ValidatesOnExceptions=True}"/> <TextBlock Text="Name"/> </StackPanel> The data class in this first example is a very simplified person class with only one property: string Name. The INotifyPropertyChanged interface is implemented and the PropertyChanged event is fired when the Name property changes. When the property changes a check is performed to see if the new string is null or empty. If this is the case a ValidationException is thrown explaining that the entered value is invalid. public class PersonData:INotifyPropertyChanged { private string _name; public string Name { get { return _name; } set { if (_name != value) { if(string.IsNullOrEmpty(value)) throw new ValidationException("Name is required"); _name = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Name")); } } } public event PropertyChangedEventHandler PropertyChanged=delegate { }; } The last thing that has to be done is letting binding an instance of the PersonData class to the DataContext of the control. This is done in the code behind file. public partial class Demo1 : UserControl { public Demo1() { InitializeComponent(); this.DataContext = new PersonData() {Name = "Johnny Walker"}; } } Error Summary In many cases you would have more than one entry control. A summary of errors would be nice in such case. With a few changes to the xaml an error summary, like below, can be added. First, add a namespace to the xaml so the control can be used. Add the following line to the header of the .xaml file. xmlns:Controls="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data.Input" Next, add the control to the layout. To get the result as in the image showed earlier, add the control right above the StackPanel from the first example. It’s got a small margin to separate it from the textbox a little. <Controls:ValidationSummary Margin="8"/> The ValidationSummary control has to be notified that an ValidationException occurred. This can be done with a small change to the xaml too. Add the NotifyOnValidationError to the binding expression. By default this value is set to false, so nothing would be notified. Set the property to true to get it to work. <TextBox Width="150" x:Name="Name" Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=True}"/> Data annotation Validating data in the setter is one option, but not my personal favorite. It’s the easiest way if you have a single required value you want to check, but often you want to validate more. Besides, I don’t consider it best practice to write logic in setters. The way used by frameworks like WCF Ria Services is the use of attributes on the properties. Instead of throwing exceptions you have to call the static method ValidateProperty on the Validator class. This call stays always the same for a particular property, not even when you change the attributes on the property. To mark a property “Required” you can use the RequiredAttribute. This is what the Name property is going to look like: [Required] public string Name { get { return _name; } set { if (_name != value) { Validator.ValidateProperty(value, new ValidationContext(this, null, null){ MemberName = "Name" }); _name = value; if (PropertyChanged != null) PropertyChanged(this, new PropertyChangedEventArgs("Name")); } } } The ValidateProperty method takes the new value for the property and an instance of ValidationContext. The properties passed to the constructor of the ValidationContextclass are very straight forward. This part is the same every time. The only thing that changes is the MemberName property of the ValidationContext. Property has to hold the name of the property you want to validate. It’s the same value you provide the PropertyChangedEventArgs with. The System.ComponentModel.DataAnnotation contains eight different validation attributes including a base class to create your own. They are: RequiredAttribute Specifies that a value must be provided. RangeAttribute The provide value must fall in the specified range. RegularExpressionAttribute Validates is the value matches the regular expression. StringLengthAttribute Checks if the number of characters in a string falls between a minimum and maximum amount. CustomValidationAttribute Use a custom method to validate the value. DataTypeAttribute Specify a data type using an enum or a custom data type. EnumDataTypeAttribute Makes sure the value is found in a enum. ValidationAttribute A base class for custom validation attributes All of these will ensure that an validation exception is thrown, except the DataTypeAttribute. This attribute is used to provide some additional information about the property. You can use this information in your own code. [Required] [Range(0,125,ErrorMessage = "Value is not a valid age")] public int Age { It’s no problem to stack different validation attributes together. For example, when an Age is required and must fall in the range from 0 to 125: [Required, StringLength(255,MinimumLength = 3)] public string Name { Or in one row like this, for a required Name with at least 3 characters and a maximum of 255: Delayed validation Having properties marked as required can be very useful. The only downside to the technique described earlier is that you have to change the value in order to get it validated. What if you start out with empty an empty entry form? All fields are empty and thus won’t be validated. With this small trick you can validate at the moment the user click the submit button. <TextBox Width="150" x:Name="NameField" Text="{Binding Name, Mode=TwoWay, ValidatesOnExceptions=True, NotifyOnValidationError=True, UpdateSourceTrigger=Explicit}"/> By default, when a TwoWay bound control looses focus the value is updated. When you added validation like I’ve shown you earlier, the value is validated. To overcome this, you have to tell the binding update explicitly by setting the UpdateSourceTrigger binding property to Explicit: private void SubmitButtonClick(object sender, RoutedEventArgs e) { NameField.GetBindingExpression(TextBox.TextProperty).UpdateSource(); } This way, the binding is in two direction but the source is only updated, thus validated, when you tell it to. In the code behind you have to call the UpdateSource method on the binding expression, which you can get from the TextBox. Conclusion Data validation is something you’ll probably want on almost every entry form. I always thought it was hard to do, but it wasn’t. If you can throw an exception you can do validation. If you want to know anything more in depth about something I talked about in this article let me know. I might write an entire post to that.

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[Windows 8] Update TextBox’s binding on TextChanged

- by Benjamin Roux

Since UpdateSourceTrigger is not available in WinRT we cannot update the text’s binding of a TextBox at will (or at least not easily) especially when using MVVM (I surely don’t want to write behind-code to do that in each of my apps !). Since this kind of demand is frequent (for example to disable of button if the TextBox is empty) I decided to create some attached properties to to simulate this missing behavior. namespace Indeed.Controls { public static class TextBoxEx { public static string GetRealTimeText(TextBox obj) { return (string)obj.GetValue(RealTimeTextProperty); } public static void SetRealTimeText(TextBox obj, string value) { obj.SetValue(RealTimeTextProperty, value); } public static readonly DependencyProperty RealTimeTextProperty = DependencyProperty.RegisterAttached("RealTimeText", typeof(string), typeof(TextBoxEx), null); public static bool GetIsAutoUpdate(TextBox obj) { return (bool)obj.GetValue(IsAutoUpdateProperty); } public static void SetIsAutoUpdate(TextBox obj, bool value) { obj.SetValue(IsAutoUpdateProperty, value); } public static readonly DependencyProperty IsAutoUpdateProperty = DependencyProperty.RegisterAttached("IsAutoUpdate", typeof(bool), typeof(TextBoxEx), new PropertyMetadata(false, OnIsAutoUpdateChanged)); private static void OnIsAutoUpdateChanged(DependencyObject sender, DependencyPropertyChangedEventArgs e) { var value = (bool)e.NewValue; var textbox = (TextBox)sender; if (value) { Observable.FromEventPattern<TextChangedEventHandler, TextChangedEventArgs>( o => textbox.TextChanged += o, o => textbox.TextChanged -= o) .Do(_ => textbox.SetValue(TextBoxEx.RealTimeTextProperty, textbox.Text)) .Subscribe(); } } } } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The code is composed of two attached properties. The first one “RealTimeText” reflects the text in real time (updated after each TextChanged event). The second one is only used to enable the functionality. To subscribe to the TextChanged event I used Reactive Extensions (Rx-Metro package in Nuget). If you’re not familiar with this framework just replace the code with a simple: textbox.TextChanged += textbox.SetValue(TextBoxEx.RealTimeTextProperty, textbox.Text); .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } To use these attached properties, it’s fairly simple <TextBox Text="{Binding Path=MyProperty, Mode=TwoWay}" ic:TextBoxEx.IsAutoUpdate="True" ic:TextBoxEx.RealTimeText="{Binding Path=MyProperty, Mode=TwoWay}" /> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Just make sure to create a binding (in TwoWay) for both Text and RealTimeText. Hope this helps !

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NInject and thread-safety

- by cbp

I am having problems with the following class in a multi-threaded environment: public class Foo { [Inject] public IBar InjectedBar { get; set; } public bool NonInjectedProp { get; set; } public void DoSomething() { /* The following line is causing a null-reference exception */ InjectedBar.DoSomething(); } public Foo(bool nonInjectedProp) { /* This line should inject the InjectedBar property */ KernelContainer.Inject(this); NonInjectedProp = nonInjectedProp; } } This is a legacy class which is why I am using property rather than constructor injection. Sometime when the DoSomething() is called the InjectedBar property is null. In a single-threaded application, everything runs fine. How can this be occuring and how can I prevent it?

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Binding Contents of a ListBox to Selected Item from Another Listbox w/JSF & Managed Beans

- by nieltown

Hi there! I currently have a JSF application that uses two listboxes. The first, say ListBox1, contains a list of manufacturers; each option comes from the database (via a method getManufacturers in a class called QueryUtil), is populated dynamically, and its value is an integer ID. This part works so far. My goal is to populate a second listbox, say ListBox2, with a list of products sold by the manufacturer. This list of products will come from the database as well (products are linked to a manufacturer via a foreign key relationship, via a method getProducts in my QueryUtil class). How do I go about doing this? Please bear in mind that I've been working with JSF for under 24 hours; I'm willing to accept the fact that I'm missing something very rudimentary. Again, I've been able to populate the list of manufacturers just fine; unfortunately, adding the Products component gives me java.lang.IllegalArgumentException: argument type mismatch faces-config.xml <managed-bean> <managed-bean-name>ProductsBean</managed-bean-name> <managed-bean-class>com.nieltown.ProductsBean</managed-bean-class> <managed-bean-scope>request</managed-bean-scope> <managed-property> <property-name>manufacturers</property-name> <property-class>java.util.ArrayList</property-class> <value>#{manufacturers}</value> </managed-property> <managed-property> <property-name>selectedManufacturer</property-name> <property-class>java.lang.Integer</property-name> <value>#{selectedManufacturer}</value> </managed-property> <managed-property> <property-name>products</property-name> <property-class>java.util.ArrayList</property-class> <value>#{products}</value> </managed-property> <managed-property> <property-name>selectedProduct</property-name> <property-class>java.lang.Integer</property-name> <value>#{selectedProducts}</value> <managed-property> </managed-bean> com.nieltown.ProductsBean public class ProductsBean { private List<SelectItem> manufacturers; private List<SelectItem> products; private Integer selectedManufacturer; private Integer selectedProduct; public ProductsBean() {} public Integer getSelectedManufacturer(){ return selectedManufacturer; } public void setSelectedManufacturer(Integer m){ selectedManufacturer = m; } public Integer getSelectedProduct(){ return selectedProduct; } public void setSelectedProduct(Integer p){ selectedProduct = p; } public List<SelectItem> getManufacturers(){ if(manufacturers == null){ SelectItem option; plans = new ArrayList<SelectItem>(); QueryUtil qu = new QueryUtil(); Map<Integer, String> manufacturersMap = qu.getManufacturers(); for(Map.Entry<Integer, String> entry : manufacturersMap.entrySet()){ option = new SelectItem(entry.getKey(),entry.getValue()); manufacturers.add(option); } } return manufacturers; } public void setManufacturers(List<SelectItem> l){ manufacturers = l; } public List<SelectItem> getProducts(){ if(products == null){ SelectItem option; products = new ArrayList<SelectItem>(); if(selectedPlan != null){ PMTQueryUtil pqu = new PMTQueryUtil(); Map<Integer, String> productsMap = pqu.getProducts(); for(Map.Entry<Integer, String> entry : productsMap.entrySet()){ option = new SelectItem(entry.getKey(),entry.getValue()); products.add(option); } } } return products; } public void setProducts(List<SelectItem> l){ products = l; } } JSP fragment <h:selectOneListbox id="manufacturerList" value="#{ProductsBean.selectedManufacturer}" size="10"> <f:selectItems value="#{ProductsBean.manufacturers}" /> </h:selectOneListbox> <h:selectOneListbox id="productList" value="#{PendingPlansBean.selectedProduct}" size="10"> <f:selectItems binding="#{ProductsBean.products}" /> </h:selectOneListbox>

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