Hi,
I got to know that, I can use SendMessage() or PostMessage() WINAPI to close other application. However, I got a question here:

If there is Modal form shown, or report preview, or I placed NODEFAULT in mainform.queryunload, the SENDMESSAGE OR POSTMESSAGE WINAPI will not able to terminate the target application.

Any ways to solve it?
Any ways to send a "message" to the target application in order the target application can check the "message" to decide unload or not?
If using POSTMESSAGE or SENDMESSAGE WINAPI, what event will be activated in order the target application "know" it should unload now?

Thank you