[RESOLVED] Byte Array Concatination

[Doogle]

Been struggling with this thread: http://www.vbforums.com/showthread.p...ding-This-Code

The code in question uses the MidB function to concatinate two Arrays together. One happens to be a Variant the other a Byte Array.

However, this works:

Private Sub Command1_Click()
Dim bytA(9) As Byte
Dim bytB(9) As Byte
Dim bytC() As Byte
Dim intI As Integer
For intI = 0 To 9
    bytA(intI) = CByte(intI + &H10)
Next intI
For intI = 0 To 9
    bytB(intI) = CByte(intI + &H20)
Next intI
bytC = MidB(bytA, 1) & MidB(bytB, 1)
For intI = 0 To UBound(bytC)
    Debug.Print Hex(bytC(intI)); " ";
Next intI
End Sub

The net result is that the Array bytC ends up containing all the elements of bytA and bytB (exactly what you'd expect if they all were string variables, rather than Byte Arrays, and Mid$ was used)

What I don't understand is why it works. The MidB documentation suggests that the first Argument should be a String and here we are giving it a byte Array.

I would have expected a Type Mismatch error. I'd have thought it would have required a BSTR pointer rather than a 'direct' pointer to the string argument.

I understand that MidB returns bytes rather than characters and is primarily used in DBCS Applications.

Are there any 'gotchas' to using this technique. In the thread I referenced above it's used to buffer incoming binary data without the need for loads of loops going through arrays to manually append data. Will it plant the odd '?' in the stream if it comes upon an invalid DBCS pair ?