Finding All of the Listeners of a Given Object

Question

I have an object (myObject) and I'm trying to find everything that is listening to any event of that object.

The following code seems to work as expected for listeners created with the AddHandler syntax; but does not report listeners created using the 'Handles' syntax.

EDIT: It appears I was incorrect. This code does work, regardless of AddHandler/Handles syntax; but it only seems to work for custom events of the object. If myObject is a control - I never see the Load() event handlers; but I will see handlers for 'MyCustomEvent'.

Can anyone tell me what I'd need to do to get those events as well?

Public Sub GetListeners(ByVal myObject As Object)
        Dim myType As Type = myObject.GetType

        Dim myFieldList As FieldInfo() = myType.GetFields(BindingFlags.Static Or BindingFlags.Instance Or BindingFlags.NonPublic)

        For Each myInfo In myFieldList               
            Dim myDelegate As [Delegate] = TryCast(myInfo.GetValue(myObject), [Delegate])

            If myDelegate IsNot Nothing Then
                For Each myItem In myDelegate.GetInvocationList
                    System.Diagnostics.Debug.WriteLine(myDelegate.GetInvocationList(0).Method.Name & "-->" & myDelegate.GetInvocationList(0).Method.DeclaringType.FullName)
                Next
            End If

            Try
                Dim eventList As EventHandlerList = DirectCast(myObject.GetType().GetProperty("Events", _
              (BindingFlags.FlattenHierarchy Or (BindingFlags.NonPublic Or BindingFlags.Instance))).GetValue(myObject, Nothing), EventHandlerList)

                myDelegate = eventList(myInfo.GetValue(myObject))
            Catch ex As Exception

            End Try


            If myDelegate IsNot Nothing Then
                For Each myItem In myDelegate.GetInvocationList
                    System.Diagnostics.Debug.WriteLine(myDelegate.GetInvocationList(0).Method.Name & "-->" & myDelegate.GetInvocationList(0).Method.DeclaringType.FullName)
                Next
            End If
        Next

    End Sub

Answer 1

Using the base types, you will get all events, but only those which actually use a private backing field containing the delegate with the listening methods. If they don't do this (consider, for example, the routed events of WPF), I think you are out of luck: Since custom events can have an arbitrary implementation of AddHandler, RemoveHandler and RaiseEvent, I don't think there is a generic way to get a list of listening methods (because there might not be such a list).