Making WCF Service reference configurable from web.config in Silverlight application

• Download How_to_Config_Service_Ref.zip - 3.5 MB

Introduction

Here I am going to demonstrate solution for common problem which most of the developers face while developing Silverlight application with WCF Service. I have search lot of forums and could not found any good solution. So I am sharing my solution to make WCF service reference configurable. It makes easy for deploying on severs like Dev, QA, UAT etc. without code modification and republish.

Background

To implement this application, I am going to use the following technologies:

• Silverlight5 for the client tier
• WCF services -HTTP Binding
• WCF RIA Service V1.0 SP2

Creating Silverlight Business Application

Create new Silverlight business application. Name it to ‘BusinessAppMVVM’.

WCF Service

Add WCF service to the solution. Name it ‘BusinessAppMVVM.AppWCFService’.

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

[OperationContract] 
string GetUserAddress(string value); 

public class CrossDomainService : ICrossDomainService 
{ 
    Message ICrossDomainService.ProvidePolicyFile() 
    { 
        FileStream filestream = File.Open(@"ClientAccessPolicy.xml", FileMode.Open); 
        // Either specify ClientAccessPolicy.xml file path properly 
        // or put that in \Bin folder of the console application 
        XmlReader reader = XmlReader.Create(filestream); 
        System.ServiceModel.Channels.Message result = Message.CreateMessage(MessageVersion.None, "", reader); 
        return result; 
    } 
}

[ServiceContract] 
public interface ICrossDomainService 
{ 
    [OperationContract] 
    [WebGet(UriTemplate = "ClientAccessPolicy.xml")] 
    Message ProvidePolicyFile(); 
} 

<?xml version="1.0" encoding="utf-8" ?>
<access-policy>
<cross-domain-access>
<policy>
<allow-from http-request-headers="*">
<domain uri="*"/>
</allow-from>
<grant-to>
<resource path="/" include-subpaths="true"/>
</grant-to>
</policy>
</cross-domain-access>
</access-policy>

<appSettings>
<!--QA Server WCF Service URL-->
<!--<add key="WCFServiceURL" value="<a href="http://test-iis-qa:1111/Service1.svc">http://Test-iis-QA:1111/Service1.svc</a />" />-->
<!--Local development WCF Service URL-->
<add key="WCFServiceURL" value="<a href="http://localhost:59761/Service1.svc">http://localhost:59761/Service1.svc</a />" />
</appSettings> 

Add following method in your new RIA service.

[Invoke]
public string GetWCFServiceAddress()
{
    string url = ConfigurationManager.AppSettings.Get("WCFServiceURL");
    return url;
}

Silverlight Client

Add service reference to Silverlight project.

Declare property in ‘app.xaml.cs’.

public string WCFServiceURL { get; set; }

Write following lines to call RIA service to get ‘WCFServiceURL’ value inside ‘Application_UserLoaded’.

//Call RIA Service to get WCF Service URL
var context = new BusinessAppMVVM.Web.Services.BusinessAppRIAContext();
context.GetWCFServiceAddress(GetWCFServiceURLCompleted, null);

Define ‘GetWCFServiceURLCompleted’ as follows.

private void GetWCFServiceURLCompleted(InvokeOperation<string> args)
{
try
{
    WCFServiceURL = args.Value;
}
catch (Exception ex)
{
    //log
}
}

Now you are all set to write testing code to call WCF service. Add button control to ‘Home.xaml’. On button click event write following line of code.

private void button1_Click(object sender, System.Windows.RoutedEventArgs e)
{
    //Create Instance.
    BusinessAppServiceModel.Service1Client _serviceClient = null;
    if (_serviceClient == null)
    {
        var myBinding = new BasicHttpBinding();
        string url = ((App)Application.Current).WCFServiceURL;
        if (url != null)
        {
        var address = new EndpointAddress(url);
        _serviceClient = new BusinessAppServiceModel.Service1Client(myBinding, address);
        }
        else
        {
        MessageBox.Show("WCF Service URL is not found.");
        }
    }
    //Call Service
    _serviceClient.GetUserAddressCompleted -=
    new EventHandler<GetUserAddressCompletedEventArgs>(OnGetUserAddressCompleted);
    _serviceClient.GetUserAddressCompleted +=
    new EventHandler<GetUserAddressCompletedEventArgs>(OnGetUserAddressCompleted);
    _serviceClient.GetUserAddressAsync("Called from UI");
}
private void OnGetUserAddressCompleted(object sender, GetUserAddressCompletedEventArgs e)
{
    MessageBox.Show(e.Result);
}

Deploy Silverlight and WCF service. Go to Web.config to change service url. You can see your project is working without redeploy.

At the End

You can download source code attached with this article. Hope this article will help you in deploying solution on different servers.

I would appreciate Vote for the Article and any comments or concerns or how things could be done better. Coming soon with my new findings.

Thanks for reading.