unit Unit1; 

interface 

uses

  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,

  StdCtrls; 

type 

  TURLLabel = class(TLabel)

    procedure WndProc(var Message : TMessage); override;

  end; 

type

  TForm1 = class(TForm)

    procedure FormCreate(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end; 

var

  Form1: TForm1; 

implementation 

{$R *.DFM} 

{ TURLLabel } 

procedure TURLLabel.WndProc(var Message: TMessage);

begin

  if (Message.Msg = CM_MOUSEENTER) then

  begin

    Font.Color := clBlue;

    Font.Style := Font.Style + [fsUnderline];

  end;

  if (Message.Msg = CM_MOUSELEAVE) then

  begin

    Font.Color := clWindowText;

    Font.Style := Font.Style - [fsUnderline];

  end;

  inherited WndProc(Message);

end; 

procedure TForm1.FormCreate(Sender: TObject);

begin

  with TURLLabel.Create(Self) do

  begin

    Parent := Self;

    Left := ;

    Top := ;

    caption := 'www.delphi3000.com';

    Cursor := crHandPoint;

  end;

end; 

end. 

procedure TControl.CMMouseEnter(var Message: TMessage);

begin

  if FParent <> nil then

    FParent.Perform(CM_MOUSEENTER, , Longint(Self)); // 把控件自己的指针当参数传过去，即表明当前消息来自于哪个控件

end;

procedure TControl.CMMouseLeave(var Message: TMessage);

begin

  if FParent <> nil then

    FParent.Perform(CM_MOUSELEAVE, , Longint(Self));

end;