Our application uses the diagram control within a docking control from Actipro. When "docking out" the diagram window, we are faced with the problem that everything needs to be layouted/rendered again because the following happens:

- The diagram docking window is removed from the MainWindow's VisualTree.
- A real window is created.
- The previous content of the diagram docking window is assigned to that new window, therefore inserted into a new Visual Tree

Due to this operation, the Mindfusion diagram needs to be layouted and rendered again

While this is a technical issue of WPF, I think this is a pretty common scenario (Diagram + Docking) and I want to know if anybody has an idea how to deal with this?

To sum this up, I want to preserve the rendering that has already be done when the diagram control is removed/inserted into a visual tree.

P.S.: Our diagram is interactive and needs input, so caching a bitmap or any similar "static" solution wouldn't be a solution for us.

didn't know anything of VisualTreeHelper.GetDrawing(...)! It is barely mentioned anywhere.
Thank you, you opened a whole new world to me

Ok, it's a bit more complex than that. A visual object might not have any associated drawing, while its child visuals have ones. Here is a class that will cache the speified visual (Diagram in your case) and later render it when required:

public class VisualCopy : FrameworkElement
{
	public VisualCopy(Visual visual)
	{
		drawing = new DrawingVisual();
		var dc = drawing.RenderOpen();
		Draw(visual, dc);
		dc.Close();
	}

	protected override void OnRender(DrawingContext drawingContext)
	{
		Draw(drawing, drawingContext);
	}

	private void Draw(Visual v, DrawingContext dc)
	{
		var tr = VisualTreeHelper.GetTransform(v);
		dc.PushTransform(tr);

		var dr = VisualTreeHelper.GetDrawing(v);
		if (dr != null)
			dc.DrawDrawing(dr);

		for (int i = 0, n = VisualTreeHelper.GetChildrenCount(v); i < n; ++i)
		{
			var c = VisualTreeHelper.GetChild(v, i) as Visual;
			if (c != null)
				Draw(c, dc);
		}

		dc.Pop();
	}

	private DrawingVisual drawing;
} 

I hope that helps,
Stoyan