How to override MeasureOverride to find the size of ItemsControl

Question

I am developing a UserControl that consists of a block with a heading and a list of items (as ItemsControl). The usercontrol is added dynamically to a canvas. I

Answer 1

Is your user control defined to change in height to reflect the size of the contents? By default your user control will be a fixed size and not change in height just because the items control has more entries.

I think you need to add your user control inside a grid before then measuring the grid. This is how I measure controls and it seems to work well, even when measuring the control directly does not work as in your case...

MyControl control1 = new MyControl();

... your setup code for control1...

Dim containerGrid As New Grid
containerGrid.Children.Add(control1)
containerGrid.Measure(New Size(Double.MaxValue, Double.MaxValue))
containerGrid.Arrange(New Rect(0, 0, Double.MaxValue, Double.MaxValue))

...now check the grid.ActualWidth and grid.ActualHeight

Answer 2

Try using ActualWidth and ActualHeight properties.

protected override Size MeasureOverride(Size availableSize)
{
   var desiredSize = new Size();
   var sideLength = Math.Min(ActualWidth, ActualHeight);

   desiredSize.Width = sideLength;
   desiredSize.Height = sideLength;

   return desiredSize;
}