Option Explicit On
Option Strict On
Imports System.IO
Imports System.Text
 
Public Class Form1
Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) _
  Handles Button2.Click
Dim a As String
test(a)
End Sub

 
Public Class Class1
 
    Public Function test(ByVal b As String) As String
        Return b
    End Function
 
End Class