关于类的入门例子(1): 继承窗体

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;


  {继承 TForm1 的类: TMyForm}
  TMyForm = class(TForm1)
     procedure Button1Click(Sender: TObject);
  end;

var
  Form1: TForm1;  //声明 TForm1 的实例
  MyForm1: TMyForm;  //声明 TMyForm 的实例
implementation

{$R *.dfm}

//Form1 上有两个按钮, Button1: 弹出信息; Button2: 创建并显示 MyForm1
procedure TForm1.Button1Click(Sender: TObject);
begin
  ShowMessage('TForm1');
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  MyForm1 := TMyForm.Create(nil);
  MyForm1.Show;
end;


{ TMyForm }
//TMyForm1 被创建后, 应该和 TForm1 一摸一样;
//Button2: 会继续创建并弹出新的 TMyForm1
//Button1: 会弹出两条信息, 因为继承了一条
procedure TMyForm.Button1Click(Sender: TObject);
begin
  inherited;  //继承 Button1 原有的功能
  ShowMessage('TMyForm');
end;

end.