求救！关于CreateWindow建立窗口失败 (50分)

各位大侠，小弟近日使用CreateWindow()来创建窗口，窗口类能注册成功，但一直无法调用CreateWindow成功
还请各位救命！！

说清楚些,贴代码!

小弟用BCB写的
HANDLE __fastcall TSnoop2k::XSocketAllocateHWnd(TObject * Obj)
{
bool ClassRegistered;
WNDCLASS TempClass;
HANDLE ClassHandle;

XSocketWindowClass.hInstance=HInstance;
XSocketWindowClass.style=0;
XSocketWindowClass.lpfnWndProc=XSocketWindowProc;
XSocketWindowClass.cbClsExtra=0;
XSocketWindowClass.cbWndExtra=0;
XSocketWindowClass.hInstance=0;
XSocketWindowClass.hIcon=0;
XSocketWindowClass.hCursor=0;
XSocketWindowClass.hbrBackground=0;
XSocketWindowClass.lpszMenuName=NULL;
XSocketWindowClass.lpszClassName="TTest";

ClassRegistered = GetClassInfo(HInstance,XSocketWindowClass.lpszClassName,&XSocketWindowClass);
if(!ClassRegistered)
if(!RegisterClass(&XSocketWindowClass))
return(0);
//XSocketWindowClass类能调用成功

ClassHandle= CreateWindow(XSocketWindowClass.lpszClassName,"",WS_POPUP,100, 100,100, 100,NULL,0,HInstance,NULL);
//ClassHandle一直为NULL
}


LRESULT __stdcall XSocketWindowProc(HANDLE ahWnd,UINT auMsg,WPARAM awParam,LPARAM alParam)
{
return(0);
}

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