How to access the main windows handle once the child window exits in a process in C#

I am starting an application in C# through Process.start(). when that application opens initially a child window runs to attempt to connect to a simulator hardware. till the child window succeeds in connecting to the hardware the child window remains in focus and the main window remains in the background. once the child window succeeds in connecting to the simulator hardware,i want to send key strokes to the main window. so i want to know the time lapse taken for it to connect to the hardware and also to capture the child window now. can anyone let me know how to do it if 开发者_开发知识库possible?

does Process.MainWindowHandle not suite your needs.