把silverlight的控件使用图像保存起来一

private void button3_Click(object sender,RoutedEventArgs e)
  {
  //截图
  WriteableBitmap wBitmap = new WriteableBitmap(border1,new MatrixTransform());
  Image img = new Image();
  img.Width = 450;
  img.Margin = new Thickness(2);
  img.source = wBitmap;
  //保存图片
  if (wBitmap != null)
  {
  SaveFileDialog saveDlg = new SaveFileDialog();
  saveDlg.Filter = "JPEG Files (*.jpeg)|*.jpeg";
  saveDlg.DefaultExt = ".jpeg";
  
if ((bool)saveDlg.ShowDialog())
  {
  using (Stream fs = saveDlg.OpenFile())
  {
  SavetoFile(wBitmap,fs);
  MessageBox.Show("图片保存成功");
  }
  }
  }
  this.stackPanel1.Children.Clear();
  this.stackPanel1.Children.Add(img);
  }