Amin Mahpour Official Blog

Implementation of Services in Silverlight with asp.net(VB.net code)

Introduction

If you search the web you can find plenty of C# samples for implementation of silverlight service but very few if not for VB.net.

here i will show you how to use services in silverlight in VB.net way.

Important notes

This walkthrough is designed for silverlight 2 beta 2 and VS 2008. If you have upgraded from silverlight 2 beta 1, I strongly recommend you to visit this post for more information on silverlight VB.net service issues and how to fix it.

The walkthrough

1. Create an ASP.net web Site (name it services) in VS2008 (do not forget to assign Visual Basic for language!)
2. Right click on asp.net Web Site in solution explorer and select add item. select Silverlight-Enabled WCF service and leave the default name (Service.svc), click add.
   
   This will create a Service.vb class as follows:

   Imports System.ServiceModel
   Imports System.ServiceModel.Activation

   <ServiceContract(Namespace:="")> _
   <AspNetCompatibilityRequirements(RequirementsMode:=AspNetCompatibilityRequirementsMode.Allowed)> _
   Public Class Service

       <OperationContract()> _
       Public Sub DoWork()
           ' Add your operation implementation here
       End Sub

       ' Add more operations here and mark them with <OperationContract()>
   
   End Class

3. Add a function called GetData under DoWork sub:
       <OperationContract()> _
       Public Function GetData(ByVal param As String) As String
           Return "Service is OK!"
       End Function
4. Right click on solution in solution explorer and select Add>New project. select silverlight application from list and name it SilverService
   
5. Click ok to create the silverlight application.
6. Right click on silverlight application and select add service reference.
7. Click discover button. and change namespace to serviceSL , this will automatically recognize your service:
   
8. Click OK.
9. open ServiceReferences.ClientConfig and in endpoint node, change the value of contract from ServiceSL.Service to SilverService.ServiceSL.Service. There is a bug in silverlight that do not type full project name before service name! if you do not change this, you will get an exception error on runtime.
10. Open page.vb
11. Add a textblock named "response":
    <TextBlock x:Name="response"></TextBlock>
12. Open up page.xaml.vb.
13. Add the following code:
    
        Private Sub Page_Loaded(ByVal sender As Object, ByVal e As System.Windows.RoutedEventArgs) Handles Me.Loaded
            Dim Service As New ServiceSL.ServiceClient
            AddHandler Service.GetDataCompleted, t color="#808080"> 
    AddressOf handle_GetData
            Service.GetDataAsync("some thing")
        End Sub

        Private Sub handle_GetData(ByVal ob As Object, ByVal e As ServiceSL.GetDataCompletedEventArgs)
            response.Text = e.Result
        End Sub

14. Build application to see the results
15. Modify these code to fit your interests! for example use LINQ and LINQ to SQL Classes to retrieve data from server securely!