ModifyMenu

The ModifyMenu function changes an existing menu item. This function is used to specify the content, appearance, and behavior of the menu item.

The ModifyMenu function has been superseded by the SetMenuItemInfo function. You can still use ModifyMenu, however, if you do not need any of the extended features of SetMenuItemInfo.

BOOL ModifyMenu(
  HMENU hMnu,       // handle to menu
  UINT uPosition,   // menu item to modify
  UINT uFlags,      // menu item flags
  UINT uIDNewItem,  // menu item identifier or handle to drop-down 
                    // menu or submenu
  LPCTSTR lpNewItem // menu item content
);

Parameters

hMnu
Handle to the menu to be changed.
uPosition
Specifies the menu item to be changed, as determined by the uFlags parameter.
uFlags
Specifies flags that control the interpretation of the uPosition parameter and the content, appearance, and behavior of the menu item. This parameter must be a combination of one of the following required values and at least one of the values listed in the following Remarks section.
Value Meaning
MF_BYCOMMAND Indicates that the uPosition parameter gives the identifier of the menu item. The MF_BYCOMMAND flag is the default if neither the MF_BYCOMMAND nor MF_BYPOSITION flag is specified.
MF_BYPOSITION Indicates that the uPosition parameter gives the zero-based relative position of the menu item.

uIDNewItem
Specifies either the identifier of the modified menu item or, if the uFlags parameter has the MF_POPUP flag set, the handle to the drop-down menu or submenu.
lpNewItem
Pointer to the content of the changed menu item. The interpretation of this parameter depends on whether the uFlags parameter includes the MF_BITMAP, MF_OWNERDRAW, or MF_STRING flag.
Value Meaning
MF_BITMAP Contains a bitmap handle.
MF_OWNERDRAW Contains a 32-bit value supplied by an application that is used to maintain additional data related to the menu item. The value is in the itemData member of the structure pointed to by the lparam parameter of the WM_MEASUREITEM or WM_DRAWITEM messages sent when the menu item is created or its appearance is updated.
MF_STRING Contains a pointer to a null-terminated string (the default).

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

If ModifyMenu replaces a menu item that opens a drop-down menu or submenu, the function destroys the old drop-down menu or submenu and frees the memory used by it.

In order for keyboard accelerators to work with bitmap or owner-drawn menu items, the owner of the menu must process the WM_MENUCHAR message. See Owner-Drawn Menus and the WM_MENUCHAR Message for more information.

The application must call the DrawMenuBar function whenever a menu changes, whether or not the menu is in a displayed window. To change the attributes of existing menu items, it is much faster to use the CheckMenuItem and EnableMenuItem functions.

The following list describes the flags that may be set in the uFlags parameter:

Value Meaning
MF_BITMAP Uses a bitmap as the menu item. The lpNewItem parameter contains the handle to the bitmap.
MF_BYCOMMAND Indicates that the uPosition parameter specifies the identifier of the menu item (the default).
MF_BYPOSITION Indicates that the uPosition parameter specifies the zero-based relative position of the new menu item.
MF_CHECKED Places a check mark next to the item. If your application provides check mark bitmaps (see the SetMenuItemBitmaps function), this flag displays a checked bitmap next to the menu item.
MF_DISABLED Disables the menu item so that it cannot be selected, but this flag does not gray it.
MF_ENABLED Enables the menu item so that it can be selected and restores it from its grayed state.
MF_GRAYED Disables the menu item and grays it so that it cannot be selected.
MF_MENUBARBREAK Functions the same as the MF_MENUBREAK flag for a menu bar. For a drop-down menu, submenu, or shortcut menu, the new column is separated from the old column by a vertical line.
MF_MENUBREAK Places the item on a new line (for menu bars) or in a new column (for a drop-down menu, submenu, or shortcut menu) without separating columns.
MF_OWNERDRAW Specifies that the item is an owner-drawn item. Before the menu is displayed for the first time, the window that owns the menu receives a WM_MEASUREITEM message to retrieve the width and height of the menu item. The WM_DRAWITEM message is then sent to the window procedure of the owner window whenever the appearance of the menu item must be updated.
MF_POPUP Specifies that the menu item opens a drop-down menu or submenu. The uIDNewItem parameter specifies the handle to the drop-down menu or submenu. This flag is used to add a menu name to a menu bar or a menu item that opens a submenu to a drop-down menu, submenu, or shortcut menu.
MF_SEPARATOR Draws a horizontal dividing line. This flag is used only in a drop-down menu, submenu, or shortcut menu. The line cannot be grayed, disabled, or highlighted. The lpNewItem and uIDNewItem parameters are ignored.
MF_STRING Specifies that the menu item is a text string; the lpNewItem parameter points to the string.
MF_UNCHECKED Does not place a check mark next to the item (the default). If your application supplies check mark bitmaps (see the SetMenuItemBitmaps function), this flag displays an unchecked bitmap next to the menu item.

The following groups of flags cannot be used together:

See Also

Menus Overview, Menu Functions, AppendMenu, CheckMenuItem, DrawMenuBar, EnableMenuItem, SetMenuItemBitmaps, SetMenuItemInfo, WM_DRAWITEM, WM_MEASUREITEM