Windows Phone 8.1 - Scanning barcode

I searched internet and found the following thread about using ZXing.Net to Scan Barcodes from Camera:

Also, I found the following article that might help:
http://www.codeproject.com/Articles/584164/Multi-Platform-Barcode-with-LEADTOOLS

So it seems that leadtools has barcode scanning feature for different platforms (including Windows Phone).

About "scan a barcode continuos" do you mean you want to read the barcode from live video preview? If yes, I think no barcode software will work with live video directly, but the solution should be easy. Simply take snapshots (still frames) from the video stream and do the barcode reading on these stills.