Most barcode scanners are just another type of input device (like a
keyboard or mouse). When they scan, they send the series of digits
that the barcode represents to the computer as keyboard input - just
as if the user had typed them.
All you need to do is set up a form with a "barcode number" input
field, which is observed for any changes. That value can be posted to
your app and you can return whatever response you want.
If you want to get funky, depending on the features of your scanner,
you can set the scanner up to send a special character code before it
sends the rest of the characters, and you could use javascript to
watch out for the special character, and capture everything that comes
after...
An image barcode reader can be integrate within .NET Framework in any
programming language, such as, C#.NET, VB.NET, ASP.NET and .NET Windows
Forms with any Visual Studio Version.