/// <summary>
/// Called when the <see cref="Children"/> collection changes.
/// </summary>
/// <param name="sender">The event sender.</param>
/// <param name="e">The event args.</param>
protected virtual void ChildrenChanged(object sender, NotifyCollectionChangedEventArgs e)
{
List <Control> controls;
switch (e.Action)
{
case NotifyCollectionChangedAction.Add:
controls = e.NewItems.OfType <Control>().ToList();
LogicalChildren.InsertRange(e.NewStartingIndex, controls);
VisualChildren.InsertRange(e.NewStartingIndex, e.NewItems.OfType <Visual>());
break;
case NotifyCollectionChangedAction.Move:
LogicalChildren.MoveRange(e.OldStartingIndex, e.OldItems.Count, e.NewStartingIndex);
VisualChildren.MoveRange(e.OldStartingIndex, e.OldItems.Count, e.NewStartingIndex);
break;
case NotifyCollectionChangedAction.Remove:
controls = e.OldItems.OfType <Control>().ToList();
LogicalChildren.RemoveAll(controls);
VisualChildren.RemoveAll(e.OldItems.OfType <Visual>());
break;
case NotifyCollectionChangedAction.Replace:
for (var i = 0; i < e.OldItems.Count; ++i)
{
var index = i + e.OldStartingIndex;
var child = (IControl)e.NewItems[i];
LogicalChildren[index] = child;
VisualChildren[index] = child;
}
break;
case NotifyCollectionChangedAction.Reset:
throw new NotSupportedException();
}
InvalidateMeasure();
}