void DestroyNativeControl()
{
if (_nativeControlHandle != null)
{
_attachment?.Dispose();
_attachment = null;
DestroyNativeControlCore(_nativeControlHandle);
_nativeControlHandle = null;
}
}
void UpdateHost()
{
_currentHost = (_currentRoot?.PlatformImpl as ITopLevelImplWithNativeControlHost)?.NativeControlHost;
var needsAttachment = _currentHost != null;
var needsShow = needsAttachment && IsEffectivelyVisible && TransformedBounds.HasValue;
if (needsAttachment)
{
// If there is an existing attachment, ensure that we are attached to the proper host or destroy the attachment
if (_attachment != null && _attachment.AttachedTo != _currentHost)
{
if (_attachment != null)
{
if (_attachment.IsCompatibleWith(_currentHost))
{
_attachment.AttachedTo = _currentHost;
}
else
{
_attachment.Dispose();
_attachment = null;
}
}
}
// If there is no attachment, but the control exists,
// attempt to attach to to the current toplevel or destroy the control if it's incompatible
if (_attachment == null && _nativeControlHandle != null)
{
if (_currentHost.IsCompatibleWith(_nativeControlHandle))
{
_attachment = _currentHost.CreateNewAttachment(_nativeControlHandle);
}
else
{
DestroyNativeControl();
}
}
// There is no control handle an no attachment, create both
if (_nativeControlHandle == null)
{
_attachment = _currentHost.CreateNewAttachment(parent =>
_nativeControlHandle = CreateNativeControlCore(parent));
}
}
else
{
// Immediately detach the control from the current toplevel if there is an existing attachment
if (_attachment != null)
{
_attachment.AttachedTo = null;
}
// Don't destroy the control immediately, it might be just being reparented to another TopLevel
if (_nativeControlHandle != null && !_queuedForDestruction)
{
_queuedForDestruction = true;
Dispatcher.UIThread.Post(CheckDestruction, DispatcherPriority.Background);
}
}
if (needsShow)
{
_attachment?.ShowInBounds(TransformedBounds.Value);
}
else if (needsAttachment)
{
_attachment?.Hide();
}
}
