unit1.pas

设计模式的源代码 Singleton模式

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Button1: TButton;
    Label1: TLabel;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Label2: TLabel;
    procedure Button1Click(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


uses SingletonUnit2, SingletonUnit1;

var
  aSingle: TSingletonl;
  acSingle: TSingletonl;
{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
  aSingle := TSingletonl.Create;
  Label1.Caption := IntToStr(Glob_Singletonlist.Count);
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  acSingle := TChildSingletonl.Create;
  Label1.Caption := IntToStr(Glob_Singletonlist.Count);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  if aSingle <> nil then
  begin
    aSingle.Destroy;
    aSingle := nil;
  end;
  Label1.Caption := IntToStr(Glob_Singletonlist.Count);
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  if acSingle <> nil then
  begin
    acSingle.Destroy;
    acSingle := nil;
  end;
  Label1.Caption := IntToStr(Glob_Singletonlist.Count);
end;

end.