1. Create a module (VB.NET in this example) or static class (C#.NET)
***IMPORTANT: Make sure it is a PUBLIC module***
2. Create a Function or Sub. Add Imports declaration. Mark each function or sub with <Extension()>
3. The first parameter in the method signature will be the object type desired (str as STRING). You can add more parameter after that one but it will not be used as an input parameter. So for example the call would be...
Dim foo as string = "ABC"
foo.StripNull("DEF")
Result----> foo = "ABCDEF"
Imports System.Runtime.CompilerServices
Public Module StringExt
<Extension()>
Public Function StripNull(str As String, otherParam as string) As String
Try
Return str.ToString + otherParam.ToString
Catch ex As Exception
Return ""
End Try
End Function
End Module