AddressOf - With a Variable?

[simonm]

I am using Visual Studio 2005.

I want to get a function reference like what the AddressOf statement returns but my function name will be stored in a variable. Does anybody know a way of doing this?

[Mr.No]

At first sight it looks like you need to read about Reflection.

[Merrion]

You need to declare a Delegate

A delegate is a type of variable that can hold a function (so long as the signature of that function matches the signature of the delegate declaration).

[Vektor]

Here is a simple delegate example

Public Class Form1
 
   Private Delegate Sub MyDelete(ByVal showText As String)
 
   Private Sub Form1_Load(ByVal sender As System.Object, _
      ByVal e As System.EventArgs) Handles MyBase.Load
      Dim oDelegateObject As New MyDelete(AddressOf MyDelegateCallback)
 
      oDelegateObject.Invoke("I am using a delegate!")
   End Sub
 
   Private Sub MyDelegateCallback(ByVal showText As String)
      MessageBox.Show(showText.Trim())
   End Sub
 
End Class

[simonm]

Vektor

That is not quite what I'm after. Say I had several functions that had the same interface as the delegate. How could I specify the function name as a string variable?

Perhaps if I gave a psudo-code example to explain what I mean:

Private Delegate Sub MyDelete(ByVal showText As String)
 
   Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
      Dim strFunctionName as String
      Dim oDelegateObject As MyDelete
      
      strFunctionName = "MyDelegateCallback"
 
      oDelegateObject = New MyDelete(AddressOf strFunctionName)
 
      oDelegateObject.Invoke("I am using a delegate!")
   End Sub
 
   Private Sub MyDelegateCallback(ByVal showText As String)
      MessageBox.Show(showText.Trim())
   End Sub

NOTE: I need the function name to be a string variable because I will be getting it from an XML file.

[jmcilhinney]

Here's a simple example using a MethodInvoker delegate. You can quite easily substitute your own.

Dim methodName As String
        Dim invoker As MethodInvoker = DirectCast([Delegate].CreateDelegate(GetType(MethodInvoker), Me.GetType(), methodName), MethodInvoker)

[simonm]

That looks like the one! Thanks.