I have a custom DrawingCanvas which is inherited from Canvas. When I add a ContentControl to DrawingCanvas with the following code nothing shows up.
GraphicsRectangle rect = new GraphicsRectangle(0, 0, 200, 200, 5, Colors.Blue);
DrawingContainer host = new DrawingContainer(rect);
ContentControl control = new ContentControl();
control.Width = 200;
control.Height = 200;
DrawingCanvas.SetLeft(control, 100);
DrawingCanvas.SetTop(control, 100);
control.Style = Application.Current.Resources["DesignerItemStyle"] as Style;
control.Content = host;
drawingCanvas.Children.Add(control);
GraphicsRectangle is a DrawingVisual and the constructor above draws a Rect with (0,0) top left point and length of 200 to the drawingContext of GraphicsRectangle. DrawingContainer is a FrameworkElement and it has one child, which is rect above, given with constructor. DrawingContainer implements GetVisualChild and VisualChildrenCount override methods. At last, Content property of ContentControl is set to the DrawingContainer to be able to show the DrawingVisual's content.
When I add the created ContentControl to a regular Canvas, control is showed correctly. I guess the reason is that DrawingCanvas doesn't implement ArrangeOverride method. It only implements MeasureOverride method. Also DrawingContainer doesn't implement Measure and
Arrange override methods. Any ideas?
