wp7取得屏幕截图的代码

public void CaptureScreen(object sender, EventArgs e)
{
　　WriteableBitmap bmp = new WriteableBitmap(480, 800);
　　bmp.Render(App.Current.RootVisual, null);
　　bmp.Invalidate();

　　MemoryStream stream = new MemoryStream();
　　bmp.SaveJpeg(stream, bmp.PixelWidth, bmp.PixelHeight, 0, 80);
　　stream.Seek(0, SeekOrigin.Begin);

　　MediaLibrary library = new MediaLibrary();
　　string filename = "ScreenShot_" + DateTime.Now.ToString("yyyy-MM-dd_hh:mm:ss");
　　library.SavePicture(filename, stream);
　　stream.Close();
}