windows phone 截屏

WriteableBitmap wb = new WriteableBitmap((int)this.ActualWidth, (int)this.ActualHeight);

wb.Render(this, null);

wb.Invalidate();

MemoryStream ms = new MemoryStream();

int h = 212;

int w = 444;

wb.SaveJpeg(ms, w, h, 0, 100); // The parameter is incorrect

BitmapImage bitmapImage = new BitmapImage();

bitmapImage.SetSource(ms);

image1.Source = bitmapImage;