Question

I understand the barcode scanner is like a keyboard and acts as such. What I need is a scanner that has some sort of api (.net/c# preferably) that i can plug into my app. Is there a particular scanner hardware vendor devs have used or are currently using, that has a .net api? or can I use any arbitrary scanner and build an api around it or use one of the open source ones?

So 1 thing I would like to do, is be able to get the value off the usb scanner without placing the cursor on the particular text field.

Thanks

Answer 1

To stay on a scanner that acts like a keyboard you could also try, to detect all key pressed within your whole application. To get a KeyPress event within your application you should set Form.KeyPreview to true and register to the above mentioned event of your form.

Now you’ll receive every key before it is send to the current active control and you can do with it, whatever you like. To prevent that it will send to the current active control after you have done your work, set e.Handled to true.

But this solution has definitely two drawbacks:

1. It only works if your application is the active window. So if the user changes the focus to another application you won’t get the key presses anymore.
2. Maybe it can become very tricky to decide if the incoming key was sent from a scanner or a user just pressed a key on his keyboard. One possibility could maybe to cache the incoming keys and measure the delta times between them, cause a human normally doesn’t enter as fast as a scanner (unless you’re maybe a secretary with 300 or more keyboard hits in a minute ;-)).