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;
Return Value
If an application processes this message, it should return zero.
Remarks
Use of the wParam and lParam parameters are summarized here.
| Message Source | wParam (high word) | wParam (low word) | lParam |
|---|
| Menu | 0 | Menu identifier (IDM_*) | 0 |
| Accelerator | 1 | Accelerator identifier (IDM_*) | 0 |
| Control | Control-defined notification code | Control identifier | Handle to the control window |
Menus
If an application enables a menu separator, the system sends a WM_COMMAND message with the low-word of the wParam parameter set to zero when the user selects the separator.
Windows 98/Me, Windows 2000/XP: If a menu is defined with a MENUINFO.dwStyle value of MNS_NOTIFYBYPOS, WM_MENUCOMMAND is sent instead of WM_COMMAND.
Accelerators
Accelerator keystrokes that select items from the window menu are translated into WM_SYSCOMMAND messages.
If an accelerator keystroke occurs that corresponds to a menu item when the window that owns the menu is minimized, no WM_COMMAND message is sent. However, if an accelerator keystroke occurs that does not match any of the items in the window's menu or in the window menu, a WM_COMMAND message is sent, even if the window is minimized.
Notification Requirements
| Minimum DLL Version |
None |
|---|
| Header | Declared in Winuser.h, include Windows.h |
|---|
| Minimum operating systems |
Windows 95, Windows NT 3.1 |
|---|
See Also