What are the different steps involved in consuming WCF service in SilverLight?

 Posted by ArticlesMaint on 9/23/2009 | Category: Silverlight Interview questions | Views: 4810

To consume WCF service is a 4 steps procedure.

Step1:- Create your WCF Service

The first step is to create your WCF service. When we create a WCF service by default it creates ‘GetData’ function which takes in a integer value and returns back a string saying “You entered 10” , in case you have passed ‘10’ as value to the function. We will try to consume this service in silverlight in the coming steps.

public class Service1 : IService1

public string GetData(int value)
return string.Format("You entered: {0}", value);

Step 2 :- Enable cross domain for your WCF service

For this example our WCF service and the silver light web application will be hosted in different IIS website. In other words they will be hosted in different domains. When we talk about different website in other words they are hosted in different domains. For instance it’s possible that your silver light web application is hosted in one domain like www.xyz.com and your WCF service is hosted in different domain i.e. www.pqr.com .

The WCF service needs to enable cross domain facility so that other domains can consume the WCF service.










Figure :- Cross domain

We need to create two XML files (clientaccesspolicy.xml and crossdomain.xml) in the root directory of the WCF service to enable cross domain functionality.

Below is the XML code snippet for clientaccesspolicy.xml.

<?xml version="1.0" encoding="utf-8" ?>

<allow-from http-request-headers="*">
<domain uri="*"/>
<resource include-subpaths="true" path="/"/>

Below is the XML code snippet for crossdomain.xml

<?xml version="1.0"?>

<!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<allow-http-request-headers-from domain="*" headers="*"/>


Step 3 :- Add the WCF service reference and call the service

Create a simple silverlight application and add the service reference to your silverlight project. In order to call the WCF service we need to define event handlers.To consume the WCF service is a three step procedure. In the first step refer the name space. In second step1 create the object of your WCF service. In the final step we need to create a event handler which will get the results sent by the WCF service.










One of the important points to note is that the function ‘GetData’ is called asynchronously.

Step 4:- Add the WCF service reference and call the service

Finally compile the program and enjoy the output.

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