Public Function CheckValidChars(ByVal text As String) As List(Of Integer)
      Dim list As New List(Of Integer)
      Dim regex As New Regex("[^a-zA-Z0-9/\-\\?:().,\'+ ]")
 
      For Each match As Match In regex.Matches(text)
         If match.Success Then list.Add(match.Index)
      Next
 
      Return list
   End Function