代表在VB.NET中

Question

I am trying to use delegate concept to dynamically AddHandler to different events, ie instead of doing

AddHandler tmrA.Elapsed, AddressOf tmrA_Tick
AddHandler tmrB.Elapsed, AddressOf tmrB_Tick


    Private Sub tmrA_Tick(ByVal sender As System.Object, ByVal e As System.Timers.ElapsedEventArgs)
' something here

    End Sub

    Private Sub tmrB_Tick(ByVal sender As System.Object, ByVal e As System.Timers.ElapsedEventArgs)
' something here

    End Sub

I was trying to do:

  Private Delegate Sub dlgtAB(ByVal sender As System.Object, ByVal e As System.Timers.ElapsedEventArgs)

and then

Private Sub Test(ByRef tmr as Timer, dlgt as dlgtAB, intInterval as integer)
    tmr = New Timer(intInterval)
    AddHandler tmr.Elapsed, dlgtAB ' getting error right here on dlgtAB
End Sub

getting the following error: Error 15 Value of type 'dlgtAB' cannot be converted to 'System.Timers.ElapsedEventHandler'.

can you tell me if this can be done and what is it that I am doing wrong

Answer 1

Don't declare your own delegate type - use the ElapsedEventHandler type:

Private Sub Test(ByRef tmr as Timer, dlgt as ElapsedEventHandler, intInterval as integer)

This will allow you to assign the appropriate handler, as the types will match.