How to kill a child process when kill the parent process

[lynn]

I'm doing a c# asp.net web application. It create a process "A" to
excute an .exe file. This exe file is compiled from c++. In this exe
file it will create another new process "B" to excute another .exe
file. (This one is VB, but I think this doesn't matter). What I want
to do is when I kill the first process "A" from c#(usill kill()
function) I want to kill the child process "B" at the same time.
If all is in c++ maybe I can figure it out but in this case I totally
have no idea. Any help will be appreciated.

Thanks

lynn