为了验证一个小问题，结果被搞糊涂了。 ( 积分: 50 )

请看下面简单代码：
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Label1: TLabel;
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure FormClose(Sender: TObject
var Action: TCloseAction);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
L:TThreadList;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
L.LockList;
try
Label1.Color:=clGreen;
Finally
L.UnlockList;
end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
L.LockList;
try
Label1.Color:=clRed;
Finally
L.UnlockList;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
L:=TThreadList.Create;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
L.LockList;
end;

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

procedure TForm1.FormClose(Sender: TObject
var Action: TCloseAction);
begin
L.Free;
end;
end.
=========================================
我的预期：Button3把L加锁，进入临界区，Button1加锁时应等待L解锁再加锁进入。即按Button3后，再按Button1，Label1的颜色不作任何改变，按Button4.解锁后，Label1颜色改变。
结果不是这样，跟加不加锁好像没关系，L居然纯粹多余。郁闷！！

请看下面简单代码：
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;
type
TForm1 = class(TForm)
Label1: TLabel;
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure FormClose(Sender: TObject
var Action: TCloseAction);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
L:TThreadList;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
L.LockList;
try
Label1.Color:=clGreen;
Finally
L.UnlockList;
end;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
L.LockList;
try
Label1.Color:=clRed;
Finally
L.UnlockList;
end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
L:=TThreadList.Create;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
L.LockList;
end;

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

procedure TForm1.FormClose(Sender: TObject
var Action: TCloseAction);
begin
L.Free;
end;
end.
=========================================
我的预期：Button3把L加锁，进入临界区，Button1加锁时应等待L解锁再加锁进入。即按Button3后，再按Button1，Label1的颜色不作任何改变，按Button4.解锁后，Label1颜色改变。
结果不是这样，跟加不加锁好像没关系，L居然纯粹多余。郁闷！！