public partial class MainPage : UserControl
    {
        public ContactContext context = new ContactContext();
        public MainPage()
        {
            InitializeComponent();
        }

        private void contactDomainDataSource_LoadedData(object sender, System.Windows.Controls.LoadedDataEventArgs e)
        {

            if (e.HasError)
            {
                System.Windows.MessageBox.Show(e.Error.ToString(), "Load Error", System.Windows.MessageBoxButton.OK);
                e.MarkErrorAsHandled();
            }
        }

        private void button1_Click(object sender, RoutedEventArgs e)
        {
           context.SubmitChanges();
        }
    }

  private void button1_Click(object sender, RoutedEventArgs e)
        {
            contactDomainDataSource.SubmitChanges();
        }

public ContactContext context;

  public MainPage()
        {
            InitializeComponent();

           context = new ContactContext();

           //теперь загружаем данные

          LoadOperation<SomeObject> lo = context.Load(context.GetSomeObjectQuery());
          dataGrid,ItemSource=lo.Entities;

        }