Force rendering of a WPF control in memory

Question

I have the following code:

void Test()
{
    currentImage.Source = GetBitmap();
    RenderTargetBitmap rtb = new RenderTargetBitmap(100, 100, 96.0, 96.0, Pix         


        

Answer 1

use a ViewBox to render in memory

Grid grid = new System.Windows.Controls.Grid() { Background = Brushes.Blue, Width = 200, Height = 200 };
Viewbox viewbox = new Viewbox();
viewbox.Child = grid; //control to render
viewbox.Measure(new System.Windows.Size(200, 200));
viewbox.Arrange(new Rect(0, 0, 200, 200));
viewbox.UpdateLayout();
RenderTargetBitmap render = new RenderTargetBitmap(200, 200, 150, 150, PixelFormats.Pbgra32);
render.Render(viewbox);

Answer 2

I think this is a BETTER answer .
The viewbox didn't work completely as expected, and it turned out to be an unnecessary overhead.

Here is a copy of that answer (instead of just link)

---

You need to force a render of the item, or wait for the item to be rendered. You can then use the ActualHeight and ActualWidth properties.

To force a render:

  MenuItem item = new MenuItem();
  item.Header = "bling";
  item.Icon = someIcon;
  //Force render
  item.Measure(new Size(Double.PositiveInfinity, Double.PositiveInfinity));
  item.Arrange(new Rect(item.DesiredSize));

In this example the MenuItem has not been given an explicit height or width. However, forcing the render will render it taking the supplied header text and icon into consideration.