Making Web Requests (Windows Phone)

Windows Phone is designed for network connectivity, and this ability can be used in games to make web requests using the Hypertext Transport Protocol (HTTP).

This topic will describe how to add HTTP web requests to your game to retrieve data, using an example that demonstrates retrieving an avatar image from XboxLIVE.com.

To make a web request on Windows Phone

1. Add a reference to the System.Net namespace in your game project.

   1. Open your project in Visual Studio, right-click References in Solution Explorer, and click Add Reference.
   2. In the .Net tab, select System.Net in the list, and click OK.

   You should see System.Net in the list of References in your project.

2. Add the System.Net namespace to any source files that will use its classes and methods.

   using System.Net;
   

3. Call HttpWebRequest.Create with a Uniform Resource Identifier (URI) to use for the request.

   // retrieve an avatar image from the Web
   string avatarUri = "https://avatar.xboxlive.com/avatar/" + gt +
       "/avatar-body.png";
   HttpWebRequest request =
       (HttpWebRequest)HttpWebRequest.Create(avatarUri);
   

4. Call HttpWebRequest.BeginGetResponse with a callback function that will receive the response from the web server in the URI.

   request.BeginGetResponse(GetAvatarImageCallback, request);
   

   Note

   For more information about working with asynchronous requests and callback functions, see Working with Asynchronous Methods in XNA Game Studio.

5. In the callback, use HttpWebRequest.EndGetResponse to get a WebResponse object, which can be used to retrieve the data returned in the response.

   Best Practice
   Be sure to catch the possible WebException that can be generated from EndGetResponse.

   void GetAvatarImageCallback(IAsyncResult result)
   {
       HttpWebRequest request = result.AsyncState as HttpWebRequest;
       if (request != null)
       {
           try
           {
               WebResponse response = request.EndGetResponse(result);
               avatarImg = Texture2D.FromStream(
                   graphics.GraphicsDevice,
                   response.GetResponseStream());
           }
           catch (WebException e)
           {
               gamerTag = "Gamertag not found.";
               return;
           }
       }
   }