Question

I have two devices(KeyBoard and BarCodeScanner) and 2 textboxes(text box 1 and text box 2).

Now I want to restrict user that he can only use keyboard in text box 1 and barcodescanner in text box 2.

How is this possible in C#?

Answer 1

You should have a look at this: Read data from Bar Code Scanner in .net (C#) windows application!

So your scanner might send special characters to help you identify it the input was from a scanner, or maybe it provides you with an additional library you could use to detect such events.
Let’s suppose thought the scanner acts identically to a keyboard without any special characters to help you know it was from a scanner and without any additional library from the manufacturer site you could use.
Then what you could use is: measure the typing speed in the KeyDown event of the second textbox.

I suspect the scanner enters the code instantly so you would have a huge typing speed measured.

Then if the typing speed is greater than a threshold ( E.g. for humans the world speed record is somewhere around 1000 characters per minute) then you delete the text that was entered.
It’s hacky, but I’ve got no better idea.