private static void OnEventNameChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs args)
{
EventTriggerBehavior behavior = (EventTriggerBehavior)dependencyObject;
if (behavior.AssociatedObject == null || behavior._resolvedSource == null)
{
return;
}
string oldEventName = (string)args.OldValue;
string newEventName = (string)args.NewValue;
behavior.UnregisterEvent(oldEventName);
behavior.RegisterEvent(newEventName);
}
private void RegisterEvent(string eventName)
{
if (string.IsNullOrEmpty(eventName))
{
return;
}
if (eventName != "Loaded")
{
Type sourceObjectType = _resolvedSource.GetType();
EventInfo info = sourceObjectType.GetRuntimeEvent(eventName);
if (info == null)
{
return;
}
MethodInfo methodInfo = typeof(EventTriggerBehavior).GetTypeInfo().GetDeclaredMethod("OnEvent");
_eventHandler = methodInfo.CreateDelegate(info.EventHandlerType, this);
_isWindowsRuntimeEvent = EventTriggerBehavior.IsWindowsRuntimeEvent(info);
if (_isWindowsRuntimeEvent)
{
_addEventHandlerMethod = add => (EventRegistrationToken)info.AddMethod.Invoke(_resolvedSource, new object[] { add });
_removeEventHandlerMethod = token => info.RemoveMethod.Invoke(_resolvedSource, new object[] { token });
WindowsRuntimeMarshal.AddEventHandler(_addEventHandlerMethod, _removeEventHandlerMethod, _eventHandler);
}
else
{
info.AddEventHandler(_resolvedSource, _eventHandler);
}
}
else if (!_isLoadedEventRegistered)
{
FrameworkElement element = _resolvedSource as FrameworkElement;
if (element != null && !EventTriggerBehavior.IsElementLoaded(element))
{
_isLoadedEventRegistered = true;
element.Loaded += OnEvent;
}
}
}
private static bool IsWindowsRuntimeEvent(EventInfo eventInfo)
{
return(eventInfo != null &&
EventTriggerBehavior.IsWindowsRuntimeType(eventInfo.EventHandlerType) &&
EventTriggerBehavior.IsWindowsRuntimeType(eventInfo.DeclaringType));
}
private static void OnSourceObjectChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs args)
{
EventTriggerBehavior behavior = (EventTriggerBehavior)dependencyObject;
behavior.SetResolvedSource(behavior.ComputeResolvedSource());
}