public void AddChild(UIElement child, int?index = null)
{
if (child == null)
{
return;
}
var currentParent = child.GetParent() as UIElement;
// Remove child from current parent, if any
if (currentParent != this && currentParent != null)
{
// ---IMPORTANT---
// This behavior is different than UWP:
// On UWP the behavior would be to throw an "Element already has a logical parent" exception.
// It is done here to align Wasm with Android and iOS where the control is
// simply "moved" when attached to another parent.
// This could lead to "child kidnapping", like the one happening in ComboBox & ComboBoxItem
this.Log().Info($"{this}.AddChild({child}): Removing child {child} from its current parent {currentParent}.");
currentParent.RemoveChild(child);
}
child.SetParent(this);
OnAddingChild(child);
if (index is int actualIndex && actualIndex != _children.Count)
{
var currentVisual = _children[actualIndex];
_children.Insert(actualIndex, child);
Visual.Children.InsertAbove(child.Visual, currentVisual.Visual);
}
internal UIElement RemoveChild(UIElement child)
{
_children.Remove(child);
child.SetParent(null);
if (Visual != null)
{
Visual.Children.Remove(child.Visual);
}
return(child);
}
