Let me explain with an example.
By variabel type I mean f. ex. Boolean, String, Integer etc....
A variabel defined as Boolean can only hold the values True or False. Asigning anything else to it would result in a runtime error and/or a syntax error.
I would like to define a variabel type that we could call BolleanExt. A variabel defined as BooleanExt can only hold the values True, False or None. Asigning any other value will result in an error.
Another example could be a variable type that can only hold the three values Abc, Def or Ghi.
Can someone give me an exaple code on how this new variabel type could be defined so I can declare variabels from it in my code the same way I declare any other ordinary variabel like: Dim var1 As String.