unit mainunit;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Edit1: TEdit;
    Label1: TLabel;
    Button3: TButton;
    Button4: TButton;
    procedure Button1Click(Sender: TObject);
    procedure FormShow(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
 Showmessage('主窗體的句柄是：'+IntToStr(Form1.Handle));
end;

procedure TForm1.FormShow(Sender: TObject);
begin
 Button1.SetFocus;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
 Showmessage('當前鼠標點擊的按鈕的句柄是：'+IntToStr(Button2.Handle));
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
 if (Application.MessageBox('是否決定改變主窗體的標題','詢問',MB_OKCANCEL + MB_OK)=ID_OK) then
   begin
    SetWindowText(Form1.Handle, Pchar(Edit1.Text));
    if (Edit1.Text='')then
     ShowMessage('用戶將主窗體的標題設置為空!')
    else
     ShowMessage('用戶將主窗體的新標題設置為：'+Edit1.Text);
    Button3.SetFocus; 
   end
   else
   begin
    ShowMessage('用戶取消了修改主窗體標題的操作!');
    Button3.SetFocus;
   end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
 Close;
end;

end.