BM_SETCHECK

wParam = (WPARAM) fCheck; /* check state */

lParam = 0; /* not used, must be zero */

An application sends a BM_SETCHECK message to place or remove a checkmark in a radio button or check box.

fCheck

Value of wParam. Specifies the check state. This parameter can be one of the following values:

Value

Meaning

0	Set the button state to unchecked.
1	Set the button state to checked.
2	Set the button state to grayed. This value can be used only if the button has the BS_3STATE or BS_AUTO3STATE style.

This message always returns zero.

The BM_SETCHECK message has no effect on push buttons.