Code:
        Dim a As String = ""
        Dim x As Integer = 0
        Dim y As String = ""
        Dim z As Integer = 0
        Dim w As String = ""
        For x = 0 To 9
            z = CInt(Val("&H" & x.ToString("00")))
            w = Chr(z).ToString
            a = a & w
            w = Int(x / 10).ToString
            a = a & w
            w = (x Mod 10).ToString
            a = a & w
        Next
In debugging I can see that w gets the expected values, but they aren't concatenated to a.

I can maybe see the 1st concatenation being a problem as w=Chr(0) is Nul, and other values are non-printable/control codes-but why does that stop the other concatenations?

If I remove the 1st concatenation then I get the expected values-but if I include it then I get no concatenation from any of the lines.

Of course I would like to know why this is happening, but even if you can't explain that maybe you can suggest another approach.

What I'm trying to do is build a translation table for COBOL packed fields. Those store digits in nybbles so I'm trying to build a table that includes the character represented by each combination of digits followed by the string containing those two digits (e.g. &H00 = the two digit string "00", &H01 = the two digit string "01", etc.). I'd then use IndexOf to find the character that represents the hex code, and Substring to return the next two characters-the 'decoded' hex.

Thanks.