The button control responds to this message by taking the action that occurs if the button is clicked by the operator. This causes the following messages to be generated:

• A WM_HELP (in Button Controls) message, if the button has a style of BS_HELP.

• A WM_SYSCOMMAND message, if the button has a style of BS_PUSHBUTTON and a style of BS_SYSCOMMAND and not a style of BS_HELP.

• A WM_COMMAND (in Button Controls) message, if the button has a style of BS_PUSHBUTTON but not a style of BS_SYSCOMMAND and not a style of BS_HELP.

• A WM_CONTROL (in Button Controls) message, whose usnotifycode is set to BN_CLICKED, if the button has a style of BS_USERBUTTON, BS_PUSHBUTTON, BS_CHECKBOX, or BS_3STATE, and not a style of BS_SYSCOMMAND or BS_HELP.