Without using openfiledialog

Question

I want to send files to my application without using openfiledialog....lost??

OK.

You select a file in my documents, in the SendTo menu, I want my application to be an option, when you select my application, the file that was selected should be add to the list box in my application, the same way it would do if I was using openfiledialog. But I want my application to run in the background, which means I don't want to use openfiledialog.

Please help??