将菜单项移到窗口的最右边.doc

对于一些特殊的菜单项，如Help菜单项，放在窗口的最右边比较好。我们可以用Windows的API函数ModifyMenu来实现，它完成对已存在菜单的菜单项设置的改变。函数ModifyMenu的原型为：
Bool  ModifyMenu( HMENU hMnu , UINT uPosition , UINT uFlags ,UINT uIDNEWItem , LPCTSTR lpNewItem );

其中
hMnu ：指得是要修改菜单的句柄
uPosition:指得是要修改菜单的菜单项索引，其值从零开始到菜单项的总数减一
uFlags:指得是新菜单项的状态和uPosition的类型
uIDNewItem：指得是新菜单的句柄
lpNewItem:指得是修改后菜单的标题

如果设置第四个参数为新菜单的句柄，程序运行时就会把菜单项改成我们重新设计的模式。

用Borland C++Builder6进行讲解。 
1、通过File|New Application创建一个新工程
2、在窗体Form1中添加MainMenu组件，通过右键弹出菜单的Menu Designer命令设计一个简单的菜单，包含两个菜单项，其Caption分别为&File和&Help.此时菜单Help的名称为Help1。
3、在Form1的OnCreate事件的处理过程中添加如下代码
void __fastcall TForm1::FormCreate( TObject *Sender )
{
    ModifyMenu( MainMenu1->Handle , 1 , MF_BYPOSITION|MF_POPUP|MF_HELP, UINT(Help1->Handle ) , "帮助(&H)");
}

//菜单的其他性质
int i;
    TMenuItem *xx;
    i = MainMenu1->Items->Count;
    Application->MessageBoxA(IntToStr( i ).c_str) , "" , MB_OK);

    xx = MainMenu1->Items->Items[0];
    Application->MessageBoxA(xx->Caption.c_str()  , "" , MB_OK);

    i = xx->Count;
    Application->MessageBoxA(IntToStr( i ).c_str() , "" , MB_OK);

    Application->MessageBoxA(xx->Items[1]->Caption.c_str()  , "" , MB_OK);

    ModifyMenu( MainMenu1->Handle , 1 , MF_BYPOSITION|MF_POPUP|MF_HELP , UINT(Help1->Handle ),"帮助(&H)");

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The ModifyMenu function has been superseded by the SetMenuItemInfo function.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 of menu
    UINT uPosition, // menu item to modify
    UINT uFlags, // menu item flags
    UINT uIDNewItem, // menu item identifier or handle of drop-down menu or submenu
    LPCTSTR lpNewItem // menu item content
   ); 

Parameters

hMnu

Identifies 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 of the drop-down menu or submenu.

lpNewItem

Points 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.
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 of 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 of 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:

?MF_BYCOMMAND and MF_BYPOSITION
?MF_DISABLED, MF_ENABLED, and MF_GRAYED
?MF_BITMAP, MF_STRING, MF_OWNERDRAW, and MF_SEPARATOR
?MF_MENUBARBREAK and MF_MENUBREAK
?MF_CHECKED and MF_UNCHECKED