WM_COMMAND message
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.
#define WM_COMMAND 0x0111
Parameters
-
wParam
-
For a description of this parameter, see Remarks.
-
lParam
-
For a description of this parameter, see Remarks.
Return value
If an application processes this message, it should return zero.
Example
BOOL AboutDlg (
HWND hDlg,
UINT message,
WPARAM wParam,
LPARAM lParam)
{
BOOL bRet = FALSE;
switch (message)
{
case WM_INITDIALOG:
bRet = TRUE;
break;
case WM_COMMAND:
if (wParam == IDOK ||
wParam == IDCANCEL)
{
EndDialog(hDlg, TRUE);
bRet = TRUE;
}
break;
}
return bRet;
}
Example taken from Windows classic samples on GitHub.
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.
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.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client |
Windows 2000 Professional [desktop apps only] |
| Minimum supported server |
Windows 2000 Server [desktop apps only] |
| Header |
|