private static void HookEvent(UIElement that, EventBinding eventBinding)
{
if (!_handlerTable.TryGetValue(that, out var subTable))
{
subTable = new Dictionary <string, EventHandlerHolder>();
_handlerTable.Add(that, subTable);
}
string eventName = eventBinding.EventName;
if (subTable.ContainsKey(eventName))
{
throw new InvalidOperationException($"An event binding for the '{eventName}' event already exists.");
}
EventHandlerHolder handlerHolder = new EventHandlerHolder(eventBinding);
subTable[eventName] = handlerHolder;
EventInfo eventInfo = that.GetType().GetEvent(eventName) ?? throw new Exception($"The target object does not have an event named '{eventName}'.");
MethodInfo methodInfo = handlerHolder.GetType().GetMethod(nameof(EventHandlerHolder.HandleEvent), BindingFlags.Instance | BindingFlags.Public);
Delegate handler = Delegate.CreateDelegate(eventInfo.EventHandlerType, handlerHolder, methodInfo);
eventInfo.AddEventHandler(that, handler);
}
private static void UnHookEvent(UIElement that, EventBinding eventBinding)
{
string eventName = eventBinding.EventName;
EventHandlerHolder handlerHolder = _handlerTable[that][eventName];
EventInfo eventInfo = that.GetType().GetEvent(eventName);
MethodInfo methodInfo = handlerHolder.GetType().GetMethod(nameof(EventHandlerHolder.HandleEvent), BindingFlags.Instance | BindingFlags.Public);
Delegate handler = Delegate.CreateDelegate(eventInfo.EventHandlerType, handlerHolder, methodInfo);
eventInfo.RemoveEventHandler(that, handler);
_handlerTable[that].Remove(eventName);
}
