为什么不能传递窗体的handle给另一个类的hwnd数据类型的变量？？？？？如何才能在另一个类中得到窗体的句柄？？

Question

为什么不能传递窗体的handle给另一个类的hwnd数据类型的变量？？？？？如何才能在另一个类中得到窗体的句柄？？

Answer 1

unit Unit1;interfaceuses
  Windows,shellapi,QMenus, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ExtCtrls, Menus, StdCtrls; //自定义消息}
const MY_MESSAGE = WM_USER + 102;
const fmsg = WM_USER + 103;
type
TNotify=class(tcomponent)
  //const fmsg = WM_USER + 102;  //
   private
    fnd:TNotifyIconData;
    fhicon:hicon;
    //fmsg:tmessage;             //'ucallbackmessage    fwnd:hwnd;                 //'窗体句柄
    fRbutoonPop:Tpopupmenu;    //'右击托盘出现的菜单
    procedure OnIconNotify(var Message: TMessage); message fmsg;
  public
    constructor create(aowner:tcomponent);override;//'''fwnd1是窗体句柄
    procedure hideform();   //'''隐藏窗体
    procedure seticon(ficon:hicon); //'''设置图标
    procedure setmessage(msg:Tmessage);  //'''设置回调函数
    procedure setwnd(fwnd1:hwnd);
    procedure showme;                    //'''显示
    procedure setRbutoonPop(popmenu:Tpopupmenu); //'''设置右击鼠标时候弹出的菜单
  end;type
  TForm1 = class(TForm)
    imgicon: TImage;
    popmenu: TPopupMenu;
    open1: TMenuItem;
    close1: TMenuItem;
    exit1: TMenuItem;
    Button1: TButton;
    procedure FormClose(Sender: TObject; var Action: TCloseAction);
    procedure Button1Click(Sender: TObject);  private
    { Private declarations }
     fnotify:tnotify;  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}procedure TForm1.FormClose(Sender: TObject; var Action: TCloseAction);
//var  fnd:TNotifyIconData;
begin
//fnd.cbsize:=sizeof(fnd);
//fnd.wnd:=form1.Handle;
//fnd.uid:=1;
//shell_notifyicon(nim_delete,@fnd);
//shell_notifyicon(nim_delete,@fnd);
end;{ TNotify }constructor TNotify.create(aowner:tcomponent);
begin
inherited create(nil);
//
//showmessage(inttostr(fwnd1));//fwnd:=fwnd1;
//FWindowHandle := AllocateHWnd(WndProc);
//inherited Create(AOwner);
//fwnd := TForm(AOwner).Handle
//fwnd:=  AllocateHWnd(OnIconNotify);
end;procedure TNotify.hideform;
begin
  showwindow(fwnd, SW_HIDE);
  Application.ShowMainForm := False;
end;procedure TNotify.OnIconNotify(var Message: TMessage);
var Busy:Boolean;
begin
   busy:=false;
  if not Busy then
    begin
    Busy:=true;
    if Message.LParam=WM_LBUTTONDOWN then
      begin
      SetForegroundWindow(fwnd);
      showmessage('fddd');
      end;
      //if Application.MessageBox('Are you sure','Exit', MB_YESNO)=IDYES then Close;
    Busy := false;
    end;
end;procedure TNotify.seticon(ficon: hicon);
begin
  fhicon:=ficon;
end;procedure TNotify.setmessage(msg: Tmessage);
begin
  //fmsg:=msg;
end;procedure TNotify.setRbutoonPop(popmenu: Tpopupmenu);
begin
  fRbutoonPop:=popmenu;
end;procedure TNotify.setwnd(fwnd1: hwnd);
begin
fwnd:=fwnd1;
//fwnd:=findwindow('tform1',nil);
end;procedure TNotify.showme;
begin
 //
  fnd.cbsize:=sizeof(fnd);
  fnd.wnd:=fwnd;
  fnd.uid:=1;
  fnd.uflags:=nif_message or nif_icon or nif_tip;
  fnd.ucallbackmessage:=fmsg;
  fnd.hIcon:=fhicon;
  shell_notifyicon(nim_add,@fnd);
end;procedure TForm1.Button1Click(Sender: TObject);
begin
//fnotify.create(nil);
  fnotify.setwnd(self.Handle) ;
  fnotify.seticon(imgicon.Picture.Icon.Handle);
  //fnotify.setmessage(MY_MESSAGE);
  fnotify.setRbutoonPop(popmenu);
 
  fnotify.showme;
   
end;end.

Answer 2

每个窗口在系统中有唯一的HANDLE，是不能重复的，只读的；

Answer 3

procedure TNotify.setwnd(fwnd1: hwnd);
begin
fwnd:=fwnd1;////////////出错出错？？？？？？？？？？？
//fwnd:=findwindow('tform1',nil);
end;