The WM_COMMAND message is sent when the user selects a command item from a menu, when a control sends a notification message to its parent window, or when an accelerator keystroke is translated.
Syntax
WM_COMMAND
WPARAM wParam
LPARAM lParam;
Parameters
wParam
The high-order word specifies the notification code if the message is from a control. If the message is from an accelerator, this value is 1. If the message is from a menu, this value is zero.
The low-order word specifies the identifier of the menu item, control, or accelerator.
lParam
Handle to the control sending the message if the message is from a control. Otherwise, this parameter is NULL.
Return Value
If an application processes this message, it should return zero.
