Hooking into windows application

[windowsdevelop]

Basically I have an application which contains various standard windows form controls. I want to be able to hook into one of the list boxes especially so I can read the currently selected item. I have been told this isn't programming for kids but I'm willing to kill for this knowledge. As far I know they all windows so they must have handle assigned to them.

 

[.paul.]

.net hwnd = listbox.handle.toint32
try sendmessage api

if you find the answer can you tell me?