protected override System.Windows.Size MeasureOverride(System.Windows.Size constraint)
{
var uiSize = new System.Windows.Size();
if (TargetElement != null)
{
TargetElement.Dispatcher.Invoke(DispatcherPriority.Normal,
new Action(() => TargetElement.Measure(constraint)));
uiSize = TargetElement.DesiredSize;
}
return(uiSize);
}