how can i control parallel port using asp.net web application using visual c#?

Answer 1

What you will have to do is create a regular desktop application that controls the port and set a web interface to turn on the process and terminate it. Use System.Diagnostic.process in C# for example to control process execution from a web interface. You will also need to change permissions on the server that runs the application mainly to elevate the ASP.NET user to an administrator. Also add the IIS to act as the operating system in the security policies. Not simple I admit but doable.