How can I simulate a button click given the handle to the button's window?

Question

I want to simulate a click on a button located in a dialog box.

I have the handle to that window. This is an Abort/Retry/Ignore kind of window.

I don't want to go with simulating a click having X and Y coordinates as it doesn't suit my needs.

Answer 1

SendMessage(hParent, WM_COMMAND, MAKEWPARAM(IdOfButton, BN_CLICKED), (LPARAM)hwndOfButton);

Typically you can get away without the hwndOfButton, if you don't know it - depends on the dialog's implementation!

It can be SendMessage or PostMessage, depending on your use case.

Answer 2

Send a BM_CLICK message to the HWND of the button:

SendMessage(hButton, BM_CLICK, 0, 0);

That causes the button to receive WM_LBUTTONDOWN and WM_LBUTTONUP messages, and the parent to receive an BN_CLICKED notification, as if the user had physically clicked on the button.