Help ! Text box that will only alow data that is scanned in by barcode scanner.

Almost all barcode scanners actually emulate keyboard entry, so I don't see how you could manage this since to the PC it is as if the scanner is "typing" the data. You COULD program the scanner to use a special prefix (or suffix), and make the textbox erase the data if it does not start with that character, which you could hide or remove after the data is accepted by the box. But this would also mean that the scanner is only usable for your application.