First Refer to below link

how to create WCF service and LinqToSQL

Step1: First Create Silverlight Project in VS2008

Step2: In Page.xaml file Drag Silverlight Datagrid control

<data:DataGrid x:Name=”gridRegister“></data:DataGrid>

Step3: Add WCF Service (Register.svc) below link will explain

how to create WCF service and LinqToSQL view this link above

Then add Below OperationContract in Register.svc

Register.svc.cs

[OperationContract]

public IEnumerable<Registration> GetRegisterationList()

{

//SilverlightDataContext is from LinQ to SQL Classes

SilverlightDataContext db = new SilverlightDataContext();

return db.Registrations;

//Registrations is table name in Linq to sql classes

}

Page.Xaml.cs

using SilverlightDB.ServiceReference1; //add this namespace

namespace SilverlightDB

{

public partial class display : UserControl

{

public Page()

{

InitializeComponent();

//RegisterClient is explain in (how to create wcf and linq to sql classes)

RegisterClient client=new RegisterClient();

client.GetRegisterationListCompleted += new EventHandler<GetRegisterationListCompletedEventArgs>(client_GetRegisterationListCompleted);

client.GetRegisterationListAsync();

}

void client_GetRegisterationListCompleted(object sender, GetRegisterationListCompletedEventArgs e)

{

//gridRegister is name of Datagrid in Page.xaml

gridRegister.ItemsSource = e.Result;

}

}

}

Step4: Hit F5 to run the Application.