LINQ to XML in Silverlight 3.0

Objective 

This article will explain how to use LINQ to XML to read data from a XML file and bind that to SILVERLIGHT 3.0 Data Grid.  XML file will be read in a WCF service and WCF service will return a List to be bind in a Grid. 

Step 1

Create a Silverlight application.  Select hosting in Web Application project option. 

 

Step 2: Add XML file in Web project.  

If you have any existing XML file add that by selecting Add Existing Item option by right clicking on WEB (SilverLightApplication1.Web) project  else select add new item option and select XML file from DATA tab. Copy paste the below XML file in your newly created XML file.  Give any name of your choice to XML file. Name I am giving is Books.Xml.

Your XML file in Web Application project must look like. 

Books.XML 

<?xml version="1.0"?>

<catalog>

  <book id="bk101">

    <author>Gambardella, Matthew</author>

    <title>XML Developer's Guide</title>

    <genre>Computer</genre>

    <price>44.95</price>

    <publish_date>2000-10-01</publish_date>

    <description>

      An in-depth look at creating applications with XML.

    </description>

  </book>

  <book id="bk102">

    <author>Ralls, Kim</author>

    <title>Midnight Rain</title>

    <genre>Fantasy</genre>

    <price>5.95</price>

    <publish_date>2000-12-16</publish_date>

    <description>

      A former architect battles corporate zombies,

      an evil sorceress, and her own childhood to become queen

      of the world.

    </description>

  </book>
  .....
  .....
  .....
</catalog>

Step 2: Creating WCF service 

Right click on Web Project and add WCF service from Web tab. Give any name of your choice, I am giving name here MyService.

 

Creating Data Contract 

This class will get serialized at client side. 

[DataContract]
    public class BooksDTO
    {
     [DataMember]
        public string Id { get; set; }
     [DataMember]
        public string Author { get; set; }
     [DataMember]
        public string Title { get; set; }
     [DataMember]
        public string Genere { get; set; }
     [DataMember]
        public string Price { get; set; }
     [DataMember]
        public string PublishDate { get; set; }
     [DataMember]
        public string Description { get; set; }
 }

Creating Service Contract 

IMyService.cs

namespace SilverlightApplication1.Web

{
    [ServiceContract]
    public interface IMyService
    {
        [OperationContract]
        List<BooksDTO> GetBookDetails();
    }
}

Creating Service Implementation 

MyService.svc.cs

using System;

using System.Collections.Generic;

using System.Linq;

using System.Runtime.Serialization;

using System.ServiceModel;

using System.Text;

using System.Web;

using System.Xml.Linq; 

namespace SilverlightApplication1.Web

{

    public class MyService : IMyService

    {

        public List<BooksDTO> GetBookDetails()

        {

            XDocument  xmlDocument  = XDocument.Load(@"c:\\Books.XML");

            var books = from r in xmlDocument.Descendants("book")

                                   select new BooksDTO

                                   {

                                       Author = r.Element("author").Value,

                                       Title = r.Element("title").Value,

                                       Genere = r.Element("genre").Value,

                                       Price = r.Element("price").Value,

                                       PublishDate = r.Element("publish_date").Value,

                                       Description = r.Element("description").Value,

                                   };

           return books.ToList();

        }

    }

}

Few points 

1. Using namespace System,.XML.Linq  to use LINQ to XML features. 
2. Load method of XDocument class is being used to load XML document. 
3. Searching for all the descendents in XML document for the element Book. And retrieving all the child elements value. 
4. Service is returning List of BooksDTO class. 

Compile the web project and after successfully compilation right click on service and view in browser. 

Step 3: Consuming in Silverlight client 

1. Add Service Reference. 
2. While adding service reference, select advanced tab and change return type from Array to List. 
3. Add Data Grid on XAML. Give any name. I am giving name here MyGrid. 
4. On page load simply bind the result returning from service to Data Grid. 
5. Make sure your startup project is SilverLightApplication1.Web and startup page is SilverLightApplicatio1Testpage.aspx . Else you might yield with Cross domain problem. 

MainPage.Xaml

<UserControl xmlns:my="clr-namespace:System.Windows.Controls;assembly=System.Windows.Controls.Data"  x:Class="SilverlightApplication1.MainPage"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    mc:Ignorable="d"
    d:DesignHeight="300" d:DesignWidth="400">
    <Grid x:Name="LayoutRoot" Background="White">
        <my:DataGrid x:Name="myGrid" AutoGenerateColumns="True" Background="Azure" ></my:DataGrid>        
    </Grid>
</UserControl>

MainPage.Xaml.CS

using System;

using System.Collections.Generic;

using System.Linq;

using System.Net;

using System.Windows;

using System.Windows.Controls;

using System.Windows.Documents;

using System.Windows.Input;

using System.Windows.Media;

using System.Windows.Media.Animation;

using System.Windows.Shapes;

using SilverlightApplication1.ServiceReference1; 

namespace SilverlightApplication1

{

    public partial class MainPage : UserControl

    {

        public MainPage()

        {

            InitializeComponent();

            MyServiceClient proxy = new MyServiceClient();

            proxy.GetBookDetailsCompleted += new EventHandler<GetBookDetailsCompletedEventArgs>(proxy_GetBookDetailsCompleted);

            proxy.GetBookDetailsAsync();

        }

        void proxy_GetBookDetailsCompleted(object sender, GetBookDetailsCompletedEventArgs e)

        {

            myGrid.ItemsSource = e.Result;

        }

    }

}

Output 

 

Conclusion 

I have explained how to return data from XML file using LINQ to XML and bind to Silverlight datagrid.  In next article I will show other CRUD operations. Thanks for reading.