WPF equivalent of WinForms Control.DrawToBitmap

Question

Hello,

Winforms controls could draw themselves to a Bitmap, using the DrawToBitmap method. What is the equivalent way to do this in WPF?

Answer 1

Hi,

One simple way of doing it as the following

        public static void CreateBitmapFromVisual(Visual target, string fileName)
        {
            if (target == null || string.IsNullOrEmpty(fileName))
            {
                return;
            }

            Rect bounds = VisualTreeHelper.GetDescendantBounds(target);

            RenderTargetBitmap renderTarget = new RenderTargetBitmap((Int32)bounds.Width, (Int32)bounds.Height, 96, 96, PixelFormats.Pbgra32);

            DrawingVisual visual = new DrawingVisual();

            using (DrawingContext context = visual.RenderOpen())
            {
                VisualBrush visualBrush = new VisualBrush(target);
                context.DrawRectangle(visualBrush, null, new Rect(new Point(), bounds.Size));
            }

            renderTarget.Render(visual);
            PngBitmapEncoder bitmapEncoder = new PngBitmapEncoder();
            bitmapEncoder.Frames.Add(BitmapFrame.Create(renderTarget));
            using (Stream stm = File.Create(fileName))
            {
                bitmapEncoder.Save(stm);
            }
        }

Regards,

Answer 2

Thanks for responding. When I tried your code, the line'

Rect bounds = VisualTreeHelper.GetDescendantBounds(target);

returned an empty Rect.

Answer 3

What element instance you passed into it? Could you show the repro code behind here?

Regards,

Answer 4

Hi Wants2Learn,

Yes, I am agree with Johnny CH, in WPF, if you want to draw itself to a Bitmap, you could use RenderTargetBitmap, refer to this class:

http://msdn.microsoft.com/en-us/library/system.windows.media.imaging.rendertargetbitmap.aspx

Best regards,

---

Sheldon _Xiao[MSFT]
MSDN Community Support | Feedback to us
Microsoft
Please remember to mark the replies as answers if they help and unmark them if they provide no help.

Answer 5

Hello,

Sorry for the delay in getting back to you. I was calling the code too early. When I moved it into a different event, it worked correctly.