How can i call a function from usercontrol 'A' in usercontrol'B' ?

Hi guys,

I don't know if this is possible or not but I have a Usercontrol that basically is a custom form. Now when I click on a button on this UserControl (lets call it 'A'), it calls another Usercontrol(lets call it 'B') which opens a new window.

Now once I close 'B', I need a function in 'A' to run immediately.

Any Ideas? I thought that there might be an event for this but there seems to be no event that deals with this.