为什么消息死循环退不出来？高手请指教

Question

unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;type
  TForm1 = class(TForm)
    Memo1: TMemo;
    Button1: TButton;
    Button2: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure StartMsg();
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}
//-------------------------------------------------------------------------
procedure TForm1.StartMsg();
var m:TMsg;
begin
  while (true) do
  begin
    GetMessage(m,Form1.Handle,0,9999);
    Application.ProcessMessages;
    memo1.Lines.Add(IntToHex(M.wParam,4)+'  '+IntToHex(M.lParam,8));
  end;
end;//-------------------------------------------------------------------------procedure TForm1.Button2Click(Sender: TObject);
begin
  //退出
  SendMessage(Form1.Handle,WM_CLOSE,0,0);
end;procedure TForm1.Button1Click(Sender: TObject);
begin
  //开始循环
  StartMsg;
end;end.