Is it possible to have a function within a function?

Question

Is it possible to have a function within a function?

Something like this:

Public Class Form1
    Private Sub button1_Click(sender As Object, e As EventAr         


        

Answer 1

It is possible to have a function within a function, called lambda expressions.

In your case, however, it is unclear to me how it can be useful.

• Lambda Expressions (Visual Basic) @ MSDN

Answer 2

It is not possible to have a fully fledged nested function definition in VB.NET. The language does support multi-line lambda expressions which look a lot like nested functions:

Private Sub button1_Click(sender As Object, e As EventArgs) Handles button1.Click
  Dim anim =
    Sub()
      Me.Refresh()
      ...
    End Sub
End Sub

There are some notable differences though:

• Cannot have a Handles clause.
• Cannot be Implements or Overrides.
• The instance of the lambda is named, not the Sub definition.
• In this case anim is actually a delegate and not a function.