say

dim ab as string()

ab=ab.distinct ()

works.

Now turn into option explicit. Well, got error. Got to use ctype. Things become

vb.net Code:
  1. ab= CType(ab.Distinct, String())

Still got error

System.InvalidCastException was unhandled
Message=Unable to cast object of type '<DistinctIterator>d__81`1[System.String]' to type 'System.String[]'.