Question

Please take a look at the following code:

Try
  Dim Reader As New System.IO.StreamReader(PositionsFileName)
  Do While Reader.Peek() <> -1
    Dim Positions() As String = Reader.ReadLine().Split("|")
    If (Positions(0) Is Nothing) Or (Positions(1) Is Nothing) Or (Positions(2) Is Nothing) Then
      ' something
    End If
  Loop
Catch ex As Exception
  ex.Source = Nothing
End Try

I am reading a file and expecting format something|something1|something2. I am trying to make it set “Nothing” to the array index which does not exists (the file format is broken), so that the If statement goes smoothly, but it seem I am doing it wrong. Can you give me some hints?

Answer 1

If you do Split("|") and there are only 2 items (for example, something|something1), Positions(2) will not be Nothing, it will just not be there. So your code will raise an exception, something about index out of bounds of the array.

If you need Positions(2) contain Nothing in this case, you code can look like this:

Dim Positions(2) As String
Dim tmpArray() As String = Reader.ReadLine().Split("|")
For i = 0 To UBound(Positions)
  If i <= UBound(tmpArray) Then
    Positions(i) = tmpArray(i)
  Else
    Positions(i) = Nothing
  End If
Next