How to remove all event handlers from an event?

Question

I have the following class

Public Class SimpleClass
    Public Event SimpleEvent()

    Public Sub SimpleMethod()
        RaiseEvent SimpleEvent()
    End S         


        

Answer 1

It is the lambda expression that is getting you into trouble here. Don't dig a deeper hole, just use AddressOf and a private method instead so you can trivially use the RemoveHandler statement.

If you absolutely have to then keep in mind that the VB.NET compiler auto-generates a backing store field for the event with the same name as the event with "Event" appended. Which makes this code work:

    Dim Obj = New SimpleClass
    AddHandler Obj.SimpleEvent, Sub()
                                    MsgBox("Hi !")
                                End Sub

    Dim fi = GetType(SimpleClass).GetField("SimpleEventEvent", BindingFlags.NonPublic Or BindingFlags.Instance)
    fi.SetValue(Obj, Nothing)

    Obj.SimpleMethod()      '' No message box

I'll reiterate that you should not do this.