Mega Code Archive
How to add items to the system menu
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How to add items to the system menu at the top left of the form.
type
TForm1 = class(TForm)
...
procedure FormCreate(Sender: TObject);
private
procedure WMSYSCOMMAND(var message: TWMSYSCOMMAND); message WM_SYSCOMMAND;
...
procedure TForm1.FormCreate(Sender: TObject);
const
MenuCaption = '&About...';
var
i: Integer;
SystemMenu: HMenu;
MENUITEMINFO: TMENUITEMINFO;
begin
SystemMenu := GetSystemMenu(Handle, False);
i := GetMenuItemCount(SystemMenu);
FillChar(MENUITEMINFO, SizeOf(MENUITEMINFO), 0);
{ Don't use SizeOf(MENUITEMINFO) because it's required for
Windows 95 }
MENUITEMINFO.cbSize := 44;
// Separator
MENUITEMINFO.fMask := MIIM_TYPE;
MENUITEMINFO.fType := MFT_SEPARATOR;
InsertMenuItem(SystemMenu, i, TRUE, MENUITEMINFO);
// Adding About now
MENUITEMINFO.fMask := MIIM_TYPE or MIIM_ID;
MENUITEMINFO.fType := MFT_STRING;
MENUITEMINFO.dwTypeData := PChar(MenuCaption);
MENUITEMINFO.cch := Length(MenuCaption);
MENUITEMINFO.wID := 1101; // ID must be < $F000
InsertMenuItem(SystemMenu, i+1, TRUE, MENUITEMINFO);
end;
procedure TForm1.WMSYSCOMMAND(var message: TWMSYSCOMMAND);
begin
inherited;
case message.CmdType of
1101: ShowMessage('About me');
end;
end;
The previous code doesn’t add a menu item to the system menu of the
application button in the taskbar (when you right-click it). It’s
because delphi creates a hidden window. You have to do the work
twice in order to add the same menu for that window. Unfortunately,
the object receiving the WM_SYSCOMMAND message is that window too :
type
TForm1 = class(TForm)
procedure FormCreate(Sender: TObject);
private
procedure OnAppMessage(var Msg: TMsg; var Handled: Boolean);
end;
...
procedure TForm1.FormCreate(Sender: TObject);
const
MenuCaption = '&About...';
var
i: Integer;
SystemMenu: HMenu;
MENUITEMINFO: TMENUITEMINFO;
begin
Application.OnMessage := OnAppMessage;
SystemMenu := GetSystemMenu(Application.Handle, False);
// same code as before
...
end;
procedure TForm1.OnAppMessage(var Msg: TMsg; var Handled: Boolean);
begin
if (Msg.message = WM_SYSCOMMAND) and (Msg.wParam = 1101) then
begin
ShowMessage('About me');
Handled := True;
end;
end
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