Communicate with shell program

Question

Hello guru's
I am new to vb.net and hope you can give help me.
I want to start a dos program from vb.net. I already now that i need to do this with process.start(). That works fine. My problem is that the program needs input ( random keyboard strokes). When the program has enough keyboard strokes it give a message.
What i would like to know is how i know that the program is finished, so i can close the process correctly.
Hope somebody can give me a hint.