DLL 中窗体消息循环求助

先不说了贴段代码吧 procedure CreateForm;stdcall;
var
 AMsg :Tmsg;
begin
  form1:=TForm1.Create(nil);
  Form1.Hide;
  while GetMessage(AMsg,0,0,0) do
  begin
    TranslateMessage(AMsg);
    DispatchMessage(AMsg);
  end;
  Form1.Free;
  ExitThread(0);
end;
function HookProc(nCode:Integer;WParam: WPARAM;LParam:LPARAM):LRESULT;stdcall;
var
  msg:PMSG;
  s:DWORD;
label
  theExit;
begin
  if fFirstTime then
  begin
     fFirstTime := false;
     windowthread:= CreateThread(nil,0,@Createform,nil,0,s);
  end;  if nCode < 0 then
    goto theExit;  msg:=PMSG(lParam);
  if nCode=HC_ACTION then
  if msg^.message = wm_keydown then
  if msg^.WParam = ord(VK_HOME) then
   begin
      if form1 <> nil then
       begin
         if form1.Visible then
            Form1.Hide
         else
            Form1.Show;
       end;   end;
  theExit:
  result := CallNextHookEx(hHk, nCode, wParam, lParam);
end;
这个是用 SetWindowsHookEx 注入后的回调大侠帮我看下啊,这段代码 有时正常 有时不正常 这为什么;哪里出题了啊