The remote server returned an error: NotFound:

      [OperationContract]
public IQueryable SelectAllTesting()
{
DataClasses1DataContext db = new DataClasses1DataContext();

return (IQueryable)(from a in db.Employees
                    join b in db.Companys on a.Employeeid equals b.Employeeid
                     select new { a.Employeeid, a.EmployeeName, b.Companyname });
}

public partial class MainPage : UserControl
    {
        ServiceReference1.Service1Client client = new ServiceReference1.Service1Client();

        public MainPage()
        {
            InitializeComponent();

        }

        void client_SelectAllTestingCompleted(object sender, ServiceReference1.SelectAllTestingCompletedEventArgs e)
        {
            MessageBox.Show(e.ToString());
            dataGrid1.ItemsSource = (IQueryable)e.Result;
            MessageBox.Show(e.ToString());
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
            client.SelectAllTestingCompleted += new EventHandler<ServiceReference1.SelectAllTestingCompletedEventArgs>(client_SelectAllTestingCompleted);
            client.SelectAllTestingAsync();
        }

    }