I have a barcode scanner (which acts like a keyboard) and of course I have a keyboard too hooked up to a computer. The software is accepting input from both the scanner and the keyboard. I need to accept only the scanner's input. The code is written in C#. Is there a way to "disable" input from the keyboard and only accept input from the scanner?

Note: Keyboard is part of a laptop...so it cannot be unplugged. Also, I tried putting the following code protected override Boolean ProcessDialogKey(System.Windows.Forms.Keys keyData) { return true; } But then along with ignoring the keystrokes from the keyboard, the barcode scanner input is also ignored.

I cannot have the scanner send sentinal characters as, the scanner is being used by other applications and adding a sentinal character stream would mean modifying other code.

Also, I cannot use the timing method of determining if the input came from a barcode scanner (if its a bunch of characters followed by a pause) since the barcodes scanned could potentially be single character barcodes.

Yes, I am reading data from a stream.

I am trying to follow along with the article: Distinguishing Barcode Scanners from the Keyboard in WinForms. However I have the following questions:

  1. I get an error NativeMethods is inaccessible due to its protection level. It seems as though I need to import a dll; is this correct? If so, how do I do it?
  2. Which protected override void WndProc(ref Message m) definition should I use, there are two implementations in the article?
  3. Am getting an error related to [SecurityPermission( SecurityAction.LinkDemand, Flags = SecurityPermissionFlag.UnmanagedCode)] error CS0246: The type or namespace name 'SecurityPermission' could not be found (are you missing a using directive or an assembly reference?). How do I resolve this error?
  4. There is also an error on the line containing: if ((from hardwareId in hardware
c# barcode-scanner
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