public static void AddHandler(this UIElement that, SW.ExtendedRoutedEvent routedEvent, Delegate handler, bool handledEventsToo)
{
if (routedEvent == null)
{
throw new ArgumentNullException("routedEvent");
}
if (handler == null)
{
throw new ArgumentNullException("handler");
}
SW.DragEventHandler dragEventHandler = handler as SW.DragEventHandler;
if (targetEvents.Contains(routedEvent) && dragEventHandler == null)
{
throw new InvalidOperationException(System.Windows.Controls.Properties.Resources.UIElementExtendedRoutedEventExtensions_TypeOfHandlerMustBeDragEventHandler);
}
if (routedEvent == SW.DragDrop.DragEnterEvent)
{
SW.DragDrop.AddDragEnterHandler(that, dragEventHandler, handledEventsToo);
}
else if (routedEvent == SW.DragDrop.DragOverEvent)
{
SW.DragDrop.AddDragOverHandler(that, dragEventHandler, handledEventsToo);
}
else if (routedEvent == SW.DragDrop.DragLeaveEvent)
{
SW.DragDrop.AddDragLeaveHandler(that, dragEventHandler, handledEventsToo);
}
else if (routedEvent == SW.DragDrop.DropEvent)
{
SW.DragDrop.AddDropHandler(that, dragEventHandler, handledEventsToo);
}
else if (routedEvent == SW.DragDrop.GiveFeedbackEvent)
{
SW.GiveFeedbackEventHandler giveFeedbackHandler = handler as SW.GiveFeedbackEventHandler;
if (giveFeedbackHandler == null)
{
throw new InvalidOperationException(System.Windows.Controls.Properties.Resources.UIElementExtendedRoutedEventExtensions_TypeOfHandlerMustBeGiveFeedbackEventHandler);
}
SW.DragDrop.AddGiveFeedbackHandler(that, giveFeedbackHandler, handledEventsToo);
}
else if (routedEvent == SW.DragDrop.QueryContinueDragEvent)
{
SW.QueryContinueDragEventHandler queryContinueFeedbackHandler = handler as SW.QueryContinueDragEventHandler;
if (queryContinueFeedbackHandler == null)
{
throw new InvalidOperationException(System.Windows.Controls.Properties.Resources.UIElementExtendedRoutedEventExtensions_TypeOfHandlerMustBeQueryContinueDragEventHandler);
}
SW.DragDrop.AddQueryContinueDragHandler(that, queryContinueFeedbackHandler, handledEventsToo);
}
}
/// <summary>
/// Returns an observable that returns a SW.DragDropKeyStates value
/// whenever it changes, even if one of the events involved
/// is handled.
/// </summary>
/// <param name="that">The element to listen to.</param>
/// <param name="initialState">The initial state SW.DragDropKeyStates.
/// </param>
/// <returns>An observable that returns a SW.DragDropKeyStates value
/// whenever it changes, even if one of the events involved
/// is handled.</returns>
internal static IObservable<SW.DragDropKeyStates> GetKeyStateChangedAlways(
this UIElement that,
SW.DragDropKeyStates initialState)
{
return
GetKeyStateChanged(that.GetMouseLeftButtonDownAlways(), that.GetMouseLeftButtonUpAlways(), that.GetKeyDownAlways(), that.GetKeyUpAlways(), initialState);
}
/// <summary>
/// Returns an observable that returns a SW.DragDropKeyStates value
/// whenever it changes, even if one of the events involved
/// is handled or occurs in a sibling.
/// </summary>
/// <param name="that">The element to listen to.</param>
/// <param name="initialState">The initial state SW.DragDropKeyStates.
/// </param>
/// <returns>An observable that returns a SW.DragDropKeyStates value
/// whenever it changes, even if one of the events involved
/// is handled.</returns>
internal static IObservable<SW.DragDropKeyStates> GetKeyStateChangedOnSelfAndSiblingsAlways(this UIElement that, SW.DragDropKeyStates initialState)
{
IEnumerable<UIElement> popupRoots =
VisualTreeExtensions.GetVisualDescendants(that)
.OfType<Popup>()
.Select(popup => popup.Child)
.Where(popupRoot => popupRoot != null);
return GetKeyStateChanged(
popupRoots
.Select(popupRoot => popupRoot.GetMouseLeftButtonDownAlways())
.Aggregate(that.GetMouseLeftButtonDownAlways(), (left, right) => left.Merge(right)),
popupRoots
.Select(popupRoot => popupRoot.GetMouseLeftButtonUpAlways())
.Aggregate(that.GetMouseLeftButtonUpAlways(), (left, right) => left.Merge(right)),
popupRoots
.Select(popupRoot => popupRoot.GetKeyUpAlways())
.Aggregate(that.GetKeyUpAlways(), (left, right) => left.Merge(right)),
popupRoots
.Select(popupRoot => popupRoot.GetKeyDownAlways())
.Aggregate(that.GetKeyDownAlways(), (left, right) => left.Merge(right)),
initialState);
}
/// <summary>
/// Returns an observable that returns a SW.DragDropKeyStates value. The
/// observable is composed of mouse down and up observables and key down
/// and up observables.
/// </summary>
/// <param name="mouseDownObservable">An event raised when a mouse
/// button is depressed.</param>
/// <param name="mouseUpObservable">An event raised when a mouse button
/// is released.</param>
/// <param name="keyDownObservable">An event raised when a key is
/// pressed down.</param>
/// <param name="keyUpObservable">An event raised when a key is
/// released.</param>
/// <param name="initialState">The initial state of the drag and
/// drop keys.</param>
/// <returns>An observable that returns a SW.DragDropKeyStates value
/// whenever it changes, even if one of the events involved
/// is handled.</returns>
private static IObservable<SW.DragDropKeyStates> GetKeyStateChanged(
IObservable<Event<MouseButtonEventArgs>> mouseDownObservable,
IObservable<Event<MouseButtonEventArgs>> mouseUpObservable,
IObservable<Event<KeyEventArgs>> keyDownObservable,
IObservable<Event<KeyEventArgs>> keyUpObservable,
SW.DragDropKeyStates initialState)
{
return
mouseDownObservable
.Select(ev => Tuple.Create(true, SW.DragDropKeyStates.LeftMouseButton))
.Merge(
mouseUpObservable
.Select(ev => Tuple.Create(false, SW.DragDropKeyStates.LeftMouseButton)))
.Merge(
keyUpObservable
.Select(ev => Tuple.Create(false, ToDragDropKeyStates(ev.EventArgs.Key))))
.Merge(
keyDownObservable
.Select(ev => Tuple.Create(true, ToDragDropKeyStates(ev.EventArgs.Key))))
.Scan<Tuple<bool, SW.DragDropKeyStates>, SW.DragDropKeyStates>(
initialState,
(acc, current) =>
{
if (current.Item1)
{
return acc | current.Item2;
}
else
{
return acc & ~current.Item2;
}
});
}
