用一个 Byte 值保存八种状态的实例:

---

准备工作:
1、在空白窗体上添加 CheckListBox1;
2、添加四个 Button, 并激活 Button1 的 OnClick 事件;
3、激活窗体的 OnCreate 事件.

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    CheckListBox1: TCheckListBox;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
var
  b: Byte;

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  CheckListBox1.Items.CommaText := 'A,B,C,D,E,F,G,H';
  Button1.Caption := '±£´æ״̬';
  Button2.Caption := '»Ö¸´×´Ì¬';
  Button3.Caption := 'È«Ñ¡';
  Button4.Caption := 'È«²»Ñ¡';
  Button1.Tag := 1;
  Button2.Tag := 2;
  Button3.Tag := 3;
  Button4.Tag := 4;
  Button2.OnClick := Button1.OnClick;
  Button3.OnClick := Button1.OnClick;
  Button4.OnClick := Button1.OnClick;

end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  if TButton(Sender).Tag = 1 then b := 0;
  for i := 0 to CheckListBox1.Count - 1 do
    case TButton(Sender).Tag of
      1: if CheckListBox1.Checked[i] then b := b or (1 shl i);
      2: CheckListBox1.Checked[i] := Odd(b shr i);
      3: CheckListBox1.Checked[i] := True;
      4: CheckListBox1.Checked[i] := False;
    end;

end;
end.

{
--------------------------------------------------------------------------------
用集合的方式重新做前一次的例子(窗体设计与测试效果同前):
--------------------------------------------------------------------------------
}

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    CheckListBox1: TCheckListBox;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation
var
  set1: set of 0..7; {准备用自定义的集合变量 set1 储存下面的 8 种状态}


{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  CheckListBox1.Items.CommaText := 'A,B,C,D,E,F,G,H';
  Button1.Caption := '保存状态';
  Button2.Caption := '恢复状态';
  Button3.Caption := '全选';   

  Button4.Caption := '全不选';
  Button1.Tag := 1;
  Button2.Tag := 2;
  Button3.Tag := 3;
  Button4.Tag := 4;
  Button2.OnClick := Button1.OnClick;
  Button3.OnClick := Button1.OnClick;
  Button4.OnClick := Button1.OnClick;

end;

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
begin
  if TButton(Sender).Tag = 1 then set1 := [];
  for i := 0 to CheckListBox1.Count - 1 do
    case TButton(Sender).Tag of
      1: if CheckListBox1.Checked[i] then Include(set1, i);
      2: CheckListBox1.Checked[i] := i in set1;
      3: CheckListBox1.Checked[i] := True;
      4: CheckListBox1.Checked[i] := False;
    end;
end;
end.