Convert Any file type to PDF in .Net


I am looking for .Net Library for converting all file type to PDF. It should also have split and merge facility. I want to include this facility into my current ASP .Net intranet and VB .Net Desktop application.

I have tried pdfforge.dll to include in my application but it doesn't have convert any file type (like .doc, .txt, .png etc..) to PDF function. Can you please help me with some example code of pdfforge to resolve this?