public IEnumerable <EventHandler> this[EventName Name]
{
get
{
/* Verify the event is accepted by this element */
var eventTarget = EventCommon.determine_target(Owner, Name);
if (eventTarget == null)
{
return(null);/* This event is not valid for the owning element */
}
if (!Map.TryGetValue(Name, out LinkedList <EventHandler> handlerList))
{
return(Array.Empty <EventHandler>());
}
return(handlerList);
}
}
public bool Add(EventName Name, EventCallback Callback)
{
/* Verify the event is accepted by this element */
var eventTarget = EventCommon.determine_target(Owner, Name);
if (eventTarget == null)
{
return(false);/* This event is not valid for the owning element */
}
if (!Map.TryGetValue(Name, out LinkedList <EventHandler> handlerList))
{/* We have no handlers for this event yet */
handlerList = new LinkedList <EventHandler>();
Map.Add(Name, handlerList);
}
/* Theres no need for CssUI to do an extra processing step on event handler callbacks now so we will just give the listener the callback */
var listener = new EventListener(Name, (Event e) => Callback.Invoke(e));
var handler = new EventHandler(listener, Callback);
handlerList.AddLast(handler);
return(true);
}
public bool Remove(EventName Name, EventCallback Callback)
{
/* Verify the event is accepted by this element */
var eventTarget = EventCommon.determine_target(Owner, Name);
if (eventTarget == null)
{
return(false);/* This event is not valid for the owning element */
}
if (!Map.TryGetValue(Name, out LinkedList <EventHandler> handlerList))
{/* We have no handlers for this event yet */
return(false);
}
bool found = false;
var node = handlerList.First;
while (node != null)
{
var handler = node.Value;
if (ReferenceEquals(Callback, handler.callback))
{
handlerList.Remove(node);
if (handler.listener != null)
{
handler.listener.removed = true;
Owner.Listeners.Remove(handler.listener);
}
found = true;
break;
}
node = node.Next;
}
return(found);
}