How to check event handler assigned or not in QuickWatch

Question

I need to know how to verify that any event handler has already been processed? (in QuickWatch)

Answer 1

I'm not sure if I understood the question correctly, but I will give him a chance:

• How to check if any event handlers are attached to the TestEvent event:

  TestEvent will be null if event handlers are not bound.

• If one handler is attached (one-click delegate) _invocationList == 0 :

  Paste the following expression into the QuickWatch expression string:

   ((System.Reflection.RuntimeMethodInfo)(((System.Delegate)(TestEvent))._methodBase)).Name 

  to find out which event handler is connected.

• If more than one handler is connected (multicast delegate) _invocationList > 0 :

  You need to look at _invocationList , for example, to check the first attached method:

   ((System.Reflection.RuntimeMethodInfo)(((System.Delegate)(((object[])(((System.MulticastDelegate)(TestEvent))._invocationList))[0]))._methodBase)).Name 

  Check other attached handlers: change the index to 1, 2, etc. or just expand each element of the _invocationList array.

As an alternative to using the Name property, which is just the name of the handler method, you can use the m_toString field, which is the signature of the method.

In all examples, replacing TestEvent with the name of your event.

[Edit] I did not understand that you are using WPF. The WPF event system is much more complicated.

Let's say you have a button and what to check if any handler is attached to the MouseLeftButtonDown event:

• Open QuickWhatch.
• Insert the name of the button variable (say button1 ).
• Scroll through the base classes until you get a UIElement . Or quickly insert this ((System.Windows.UIElement)(button1)).EventHandlersStore into the expression.
• Find and deploy the EventHandlersStore property.
• Expand _entries .
• Expand _mapStore .
• Expand [MS.Utility....]
• You will see a list of _entry0 , _entry1 , ... _entry_n . Each of them is all events that the button also assigns to handlers.
• To find out which handlers are assigned, expand the specific _listStore => _listStore .
• You will again see the list _entry0 , _entry1 .... These are all the handlers associated with this particular event.