Delphi XE - 無法刪除系統菜單中的項目

Question

我有以下代碼，它將項目添加到系統菜單。我的問題是DeleteMenu（SysMenu，cLANGMENU，MF_BYCOMMAND）沒有刪除添加到系統菜單的彈出式菜單。我不能理解的是，爲什麼工作項目（掃描組件）添加，但不是「程序語言」

procedure TForm1.Button1Click(Sender: TObject); 
const aBaseItem : string = 'Programm-Sprache'; 
     cSepSYSTEM_MENU = wm_user + 100; 
     cScanCompSystemMenu = wm_user + 101; 
     cLANGMENU = wm_user + 102; 
     SC_ITEM = $FF00; 
var 
    MenuItemInfo: TMenuItemInfo; 
    PopupMenu: HMENU; 
    Result: Boolean; 
    SysMenu: HMenu; 
    iPos, NumItems : Integer; 
    wTemp1, wtemp2 : string; 
    Buffer: array[0..79] of Char; 
begin 
    {Create the popup menu} 
    PopupMenu := CreatePopupMenu; 
    {Insert an item into it} 
    for iPos := 5 downto 0 do 
    begin 
    FillChar(MenuItemInfo, SizeOf(MenuItemInfo), iPos); 
     with MenuItemInfo do 
     begin 
     cbSize := SizeOf(MenuItemInfo); 
     fMask := MIIM_TYPE or MIIM_ID; 
     fType := MFT_STRING; 
     wID := SC_ITEM + iPos; 
     dwTypeData := PChar(inttostr(iPos)); 
     cch := Length(dwTypeData) * 2 + 2; //4; {'Item' is 4 chars} 
     end; 
    Result := InsertMenuItem(PopupMenu, 0, True, MenuItemInfo); 
    Assert(Result, 'InsertMenuItem failed'); 
    end; 

    SysMenu := GetSystemMenu(Handle, False); 
    //why this isn't working??? 
    if not DeleteMenu(SysMenu, cLANGMENU, MF_BYCOMMAND) then 
    begin 
    ShowMessage('System Error Message: '+ SysErrorMessage(GetLastError)) ; 
    //error message is - operation completed succesfully 
    end; 

    {Insert the popup into the system menu} 
    FillChar(MenuItemInfo, SizeOf(MenuItemInfo), 0); 
    with MenuItemInfo do 
    begin 
    cbSize := SizeOf(MenuItemInfo); 
    fMask := MIIM_SUBMENU or MIIM_TYPE or MIIM_ID; 
    fType := MFT_STRING; 
    hSubMenu := PopupMenu; 
    wId := cLANGMENU; 
    dwTypeData := PChar('Test');//Before editing the question it was Program Language 
    cch := Length(dwTypeData) * 2 + 2; //7; {'SubMenu' is 7 chars} 
    end; 

    Assert(SysMenu <> 0); 
    Result := InsertMenuItem(SysMenu, GetMenuItemCount(SysMenu), True, MenuItemInfo); 
    Assert(Result, 'InsertMenuItem failed'); 


     SysMenu := GetSystemMenu(Handle, False); 
    //delete menu if exists - this is working 
    DeleteMenu(SysMenu,cSepSYSTEM_MENU,MF_SEPARATOR); 
    DeleteMenu(SysMenu,cScanCompSystemMenu,MFT_STRING); 
    //add new ones 
    InsertMenu(SysMenu, Word(-1), MF_SEPARATOR, cSepSYSTEM_MENU, ''); 
    FillChar(MenuItemInfo, SizeOf(TMenuItemInfo), #0); 
    with MenuItemInfo do 
    begin 
    cbSize := SizeOf(TMenuItemInfo); 
    fMask := MIIM_TYPE or MIIM_ID or MIIM_STATE; 
    fType := MFT_STRING; 
    wId := cScanCompSystemMenu; 
    dwTypeData := PChar('Scan components'); 
    cch := Length('Scan components'); 
    end; 
    Result := InsertMenuItem(SysMenu, GetMenuItemCount(SysMenu), True, MenuItemInfo); 
    Assert(Result, 'InsertMenuItem failed'); 
end; 

LE：此代碼運行幾次，所以我需要刪除添加的項目每一次。 LE2：即使這個代碼是在Delphi（Object Pascal）中編寫的，它也會從Windows調用WinApi函數。也許有人在這方面工作過很多，而且是一名C/C++程序員可以提供幫助。

Answer 1

根據Rob Kennedy和David Heffernan的回答，我解決了它。解決辦法不是刪除菜單項，而是獲取新的系統菜單句柄。代碼如下：

procedure TForm1.Button1Click(Sender: TObject); 
const 
     cSepSYSTEM_MENU = wm_user + 100; 
     cScanCompSystemMenu = wm_user + 101; 
     cLANGMENU = 65444; 
     SC_ITEM = $FF00; 
var 
    MenuItemInfo: TMenuItemInfo; 
    PopupMenu: HMENU; 
    Result: Boolean; 
    SysMenu: HMenu; 
    iPos, NumItems : Integer; 
    wTemp1, wtemp2 : string; 
    Buffer: array[0..79] of Char; 
    subMenu : HMENU; 
begin 

    SysMenu := GetSystemMenu(Handle, True); 
    SysMenu := GetSystemMenu(Handle, False); 

    //add new ones 
    InsertMenu(SysMenu, Word(-1), MF_SEPARATOR, cSepSYSTEM_MENU, ''); 
    FillChar(MenuItemInfo, SizeOf(TMenuItemInfo), #0); 
    with MenuItemInfo do 
    begin 
    cbSize := SizeOf(TMenuItemInfo); 
    fMask := MIIM_TYPE or MIIM_ID or MIIM_STATE; 
    fType := MFT_STRING; 
    wId := cScanCompSystemMenu; 
    dwTypeData := PChar('Scan components'); 
    cch := Length('Scan components'); 
    end; 
    Result := InsertMenuItem(SysMenu, GetMenuItemCount(SysMenu), True, MenuItemInfo); 
    Assert(Result, 'InsertMenuItem failed'); 

    {Create the popup menu} 
    PopupMenu := CreatePopupMenu; 
    {Insert an item into it} 
    for iPos := Random(10) downto 0 do 
    begin 
    FillChar(MenuItemInfo, SizeOf(MenuItemInfo), 0); 
     with MenuItemInfo do 
     begin 
     cbSize := SizeOf(MenuItemInfo); 
     fMask := MIIM_TYPE or MIIM_ID; 
     fType := MFT_STRING; 
     wID := SC_ITEM + iPos; 
     dwTypeData := PChar(inttostr(iPos)); 
     cch := Length(dwTypeData) * 2 + 2; //4; {'Item' is 4 chars} 
     end; 
    Result := InsertMenuItem(PopupMenu, 0, True, MenuItemInfo); 
    Assert(Result, 'InsertMenuItem failed'); 
    end; 

    FillChar(MenuItemInfo, SizeOf(MenuItemInfo), 0); 
    with MenuItemInfo do 

    begin 
    cbSize := SizeOf(MenuItemInfo); 
    fMask := MIIM_SUBMENU or MIIM_TYPE; 
    fType := MFT_STRING; 
    hSubMenu := PopupMenu; 
    wId := cLANGMENU; 
    dwTypeData := PChar('Programm-Language'); 
    cch := Length(dwTypeData) * 2 + 2; //7; {'SubMenu' is 7 chars} 
    end; 

    Assert(SysMenu <> 0); 
    Result := InsertMenuItem(SysMenu, GetMenuItemCount(SysMenu), True, MenuItemInfo); 
    Assert(Result, 'InsertMenuItem failed'); 
end; 

Answer 2

Delphi XE2 - 點擊該按鈕每次都會添加一個Program Language系統菜單項，並且對Scan components不起作用，儘管您說它已被刪除。

我建議這是因爲Scan components是沒有子菜單的頂級菜單項，而「程序語言」有子菜單項0 - > 5.我懷疑如果你先刪除它們，你應該然後能夠刪除父菜單（嗯，不應該清理它自己的孩子？）。

我很抱歉，但我沒有時間編碼/驗證這一點，因爲我有一個要趕上的航班，我們似乎有不同的行爲與不同的德爾福版本 - 但這是兩者之間的區別和你應該看着。

我希望我能有更多的幫助。

Answer 3

The documentation表示您需要將miim_ID標誌設置爲使用wID。沒有它，操作系統會忽略該字段，所以您創建的菜單項不會獲得您指定的ID值。因此，您進一步試圖通過該ID引用該項目失敗。

您在添加「掃描組件」項目時設置了該標誌，但省略了「測試」項目。

您可以致電GetSystemMenu(Handle, True)讓自己更容易。這會在您每次調用菜單時重置菜單，因此您不必撤消任何以前的定製。