转载一段点击后不会关闭菜单的代码

stackoverflow上找的, 核心思想是用钩子拦截菜单消息处理, 在鼠标点击后不执行默认的关闭处理

效果还行, 但是有个问题就是点击了以后不会刷新菜单(切换check状态)

暂时用不到, 留个档, 原文地址: https://stackoverflow.com/questions/5983217/how-to-select-a-menu-item-without-closing-the-menu

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Menus, ExtCtrls;

type
  TForm1 = class(TForm)
    PopupMenu1: TPopupMenu;
    Item1Normal1: TMenuItem;
    Item2NoClose1: TMenuItem;
    Item3NoClose1: TMenuItem;
    Panel1: TPanel;
    procedure Panel1ContextPopup(Sender: TObject; MousePos: TPoint;
      var Handled: Boolean);
  private
    FGetPopupWindowHandle: Boolean;
    FPopupWindowHandle: HWND;
    OrgPopupWindowProc, HookedPopupWindowProc: Pointer;
    FSelectedItemID: UINT;
    procedure WmInitMenuPopup(var Msg: TWMInitMenuPopup); message WM_INITMENUPOPUP;
    procedure WmEnterIdle(var Msg: TWMEnterIdle); message WM_ENTERIDLE;
    procedure WmMenuSelect(var Msg: TWMMenuSelect); message WM_MENUSELECT;
    procedure PopupWindowProc(var Msg: TMessage);
    procedure MenuSelectPos(Menu: TMenu; ItemPos: UINT; out CanClose: Boolean);
    procedure MenuSelectID(Menu: TMenu; ItemID: UINT; out CanClose: Boolean);
  public
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Panel1ContextPopup(Sender: TObject; MousePos: TPoint;
  var Handled: Boolean);
var
  Pt: TPoint;
begin
  Pt := (Sender as TPanel).ClientToScreen(MousePos);
  TrackPopupMenu(PopupMenu1.Handle, 0, Pt.X, Pt.Y, 0, Handle, nil);
end;

procedure TForm1.WmInitMenuPopup(var Msg: TWMInitMenuPopup);
begin
  inherited;
  if Msg.MenuPopup = PopupMenu1.Handle then
    FGetPopupWindowHandle := True;
end;

procedure TForm1.WmEnterIdle(var Msg: TWMEnterIdle);
begin
  inherited;
  if FGetPopupWindowHandle then begin
    FGetPopupWindowHandle := False;
    FPopupWindowHandle := Msg.IdleWnd;

    HookedPopupWindowProc := classes.MakeObjectInstance(PopupWindowProc);
    OrgPopupWindowProc := Pointer(GetWindowLong(FPopupWindowHandle, GWL_WNDPROC));
    SetWindowLong(FPopupWindowHandle, GWL_WNDPROC, Longint(HookedPopupWindowProc));
  end;
end;

procedure TForm1.WmMenuSelect(var Msg: TWMMenuSelect);
begin
  inherited;
  if Msg.Menu = PopupMenu1.Handle then
    FSelectedItemID := Msg.IDItem;
end;


const
  { Undocumented Menu Messages }
  MN_SETHMENU                 = $01E0;
  MN_GETHMENU                 = $01E1;
  MN_SIZEWINDOW               = $01E2;
  MN_OPENHIERARCHY            = $01E3;
  MN_CLOSEHIERARCHY           = $01E4;
  MN_SELECTITEM               = $01E5;
  MN_CANCELMENUS              = $01E6;
  MN_SELECTFIRSTVALIDITEM     = $01E7;
  MN_GETPPOPUPMENU            = $01EA;
  MN_FINDMENUWINDOWFROMPOINT  = $01EB;
  MN_SHOWPOPUPWINDOW          = $01EC;
  MN_BUTTONDOWN               = $01ED;
  MN_MOUSEMOVE                = $01EE;
  MN_BUTTONUP                 = $01EF;
  MN_SETTIMERTOOPENHIERARCHY  = $01F0;
  MN_DBLCLK                   = $01F1;

procedure TForm1.PopupWindowProc(var Msg: TMessage);
var
  NormalItem: Boolean;
begin
  case Msg.Msg of
    MN_BUTTONDOWN:
      begin
        MenuSelectPos(PopupMenu1, UINT(Msg.WParamLo), NormalItem);
        if not NormalItem then
          Exit;
      end;
    WM_KEYDOWN:
      if Msg.WParam = VK_RETURN then begin
        MenuSelectID(PopupMenu1, FSelectedItemID, NormalItem);
        if not NormalItem then
          Exit;
      end;
    WM_DESTROY:
      begin
        SetWindowLong(FPopupWindowHandle, GWL_WNDPROC, Longint(OrgPopupWindowProc));
        classes.FreeObjectInstance(HookedPopupWindowProc);
      end;
  end;

  Msg.Result := CallWindowProc(OrgPopupWindowProc, FPopupWindowHandle,
      Msg.Msg, Msg.WParam, Msg.LParam);

end;


procedure TForm1.MenuSelectID(Menu: TMenu; ItemID: UINT; out CanClose: Boolean);
var
  Item: TMenuItem;
begin
  CanClose := True;
  Item := Menu.FindItem(ItemID, fkCommand);
  if Assigned(Item) then begin
    // Menu Item is clicked
    Item.Click;
//    Panel1.Caption := Item.Name;
    CanClose := Item = Item1Normal1;
  end;
end;

procedure TForm1.MenuSelectPos(Menu: TMenu; ItemPos: UINT; out CanClose: Boolean);
begin
  MenuSelectID(Menu, GetMenuItemID(Menu.Handle, ItemPos), CanClose);
end;

end.