This message occurs when the user selects an item from a menu, when a control passes a message to its parent window, or when an accelerator key stroke is translated.
| Parameter | Description |
| wParam | Contains the menu item, the control ID, or the accelerator ID. | |
| lParam | Specifies whether the message is from a menu, an accelerator, or a control. The low-order word contains zero if the message is from a menu. The high-order word contains 1 if the message is an accelerator message. If the message is from a control, the high-order word of the lParam parameter contains the notification code. The low-order word is the window handle of the control sending the message. |
Accelerator key strokes that are defined to select items from the System menu are translated into WM_SYSCOMMAND messages.
If an accelerator key stroke that corresponds to a menu item occurs when the window that owns the menu is minimized, no WM_COMMAND message is sent. However, if an accelerator key stroke that does not match any of the items on the window's menu or on the System menu occurs, a WM_COMMAND message is sent, even if the window is minimized.