pop data in combo in silverlight

//Service File Code
[OperationContract]
       public List<comboFill> GetBranch()
       {
           using (Entities context = new Entities())
           {
               return (from c in context.BranchMasters
                       select new comboFill
                       {
                           Name=c.Name,
                       }).Take<comboFill>(10).ToList<comboFill>();
           }
       }
public class comboFill
       {
           public string Name { get; set; }
       }

//Form Code
private void Page_Loaded(object sender, RoutedEventArgs e)
{

    var client= new ServiceReference1.AlumniServiceClient();

    client.GetBranchCompleted += (s, ea) =>
        {

           // cboBranch.Items.Add(ea.Result);
            dataGrid1.AutoGenerateColumns = true;
            dataGrid1.ItemsSource = ea.Result;
        };
    client.GetBranchAsync();
}