Hey , i am new to visual basic.NET , i want to recognize a barcode device in VB.NET , further have to generate some barcodes using VB.NET and recognize barcodes through barcode device. so anyone can help me... Thank you

To generate barcodes you can use free3of9 barcode font. Its completely free and I've used on several projects to create scanner readable barcodes.

We rarely need to recognise barcode devices in programming. They usually simulate keyboard entry and you accept their input as would with normal keyboard.
To generate barcodes as hericles said you need a font. A free 3of9 font will do the job, usually by starting and ending your string with stars ( * ).

PS: Depending on the application a 3of9 font might not do the trick for you. There might be standards you have to follow or all your devices are setup for a particular encoding and you need to follow that. Whatever the case it's just a font.
PS2: The font that you'll use needs to be installed in all computers displaying / printing the barcode or you'll get the text version of your stirng. You don't need anything for just reading the barcode.

So far everyone has been assuming you want 3 of 9 barcodes, which isn't necessarily a safe assumption. If 3 or 9 or another simple linear barcode symbology is acceptable then it can be as easy as adam_k suggested: barcode readers are usually USB and send translated results directly through standard input as if it were a keyboard. Printing barcodes is equally trivial given a font and minimal formatting efforts (ie. the asterisk wrapping for 3 of 9).

However, if you need to use stacked or 2D barcodes things get harder because there are encoding steps involved. For example, the PDF417 symbology uses a complex algorithm to produce the encoded result, which is then displayed by the font. Without the encoding, readers will fail to recognize the barcode. This is where it makes sense to use a library to do the heavy lifting.

For creating Bar Codes ( either 2D and also 3D bar codes ) I've used the bar code library from Tal Tech. Check them out at http://www.taltech.com They also offer bar code reader devices.