UpdateLayeredWindow在别的机器上执行吧不成功
在自己的机器上测试没问题，在别的机器上（xp sp2、sp3）测试，该函数返回0，调用失败，使用GetLastError（）获得0，表示没有错误发生，但就是不能显示窗体
图片是PNG的，有渐变透明效果，已经是release版本，

C/C++ code

void SkinManager::UpdateDisplay( LPWNDINFO wndinfo,DWORD dwButton ){    if (wndinfo->hWnd){        if (bFlagRead){            if (wndinfo->lpWndType == wstring(_T("StatusWindow"))){                m_BakWidth  = m_pStatusImg->GetWidth();                m_BakHeight = m_pStatusImg->GetHeight();            }            if ( wndinfo->lpWndType == wstring(_T("CCWindow"))){                SkinManager::m_BakWidth  = wndinfo->szWnd.cx;                SkinManager::m_BakHeight = wndinfo->szWnd.cy;            }            ::SetWindowPos(wndinfo->hWnd, NULL, wndinfo->ptWnd.x, wndinfo->ptWnd.y,m_BakWidth, m_BakHeight,SWP_NOACTIVATE);            HDC hdcTemp, m_hdcMemory, hdcScreen;            PAINTSTRUCT ps;            hdcTemp = BeginPaint(wndinfo->hWnd, &ps);            HBITMAP hBitMap = CreateCompatibleBitmap(hdcTemp, m_BakWidth, m_BakHeight);            m_hdcMemory = CreateCompatibleDC(hdcTemp);//创建与显示设备相关的内存设备上下文            SelectObject(m_hdcMemory, hBitMap);            hdcScreen = GetDC (wndinfo->hWnd);            //得到窗体的区域            RECT rct;            GetWindowRect(wndinfo->hWnd,&rct);            POINT ptWinPos = {rct.left,rct.top};            Graphics graph(m_hdcMemory);                Point points[] = { Point(0, 0),Point(m_BakWidth, 0),Point(0, m_BakHeight)};                graph.DrawImage(m_pCCWndImg, points, 3);                int iImageX =rct.right - rct.left - m_pOther->GetWidth()-10;                graph.DrawImage(m_pOther,iImageX,15,200,50);                //输出字符串                if (wndinfo->strResultComp !=_T("")){                    FontFamily     fontFamily(_T("Arial"));                    Gdiplus::Font  font(&fontFamily, 16,FontStyleRegular, UnitPixel);                    PointF      pointFComp(wndinfo->ptStrComp.x, wndinfo->ptStrComp.y);                    PointF      pointFCand(wndinfo->ptStrCand.x, wndinfo->ptStrCand.y);                    SolidBrush  solidBrush(Color(255, 255, 255, 255));                    graph.SetTextRenderingHint(TextRenderingHintAntiAlias);                    graph.DrawString(wndinfo->strResultComp.c_str(), -1, &font, pointFComp, &solidBrush);                    graph.DrawString(wndinfo->strResultCand.c_str(), -1, &font, pointFCand, &solidBrush);                }            SIZE sizeWindow = {m_BakWidth,m_BakHeight};            POINT ptSrc = {0,0};            DWORD dwExStyle=GetWindowLong(wndinfo->hWnd,GWL_EXSTYLE);            if((dwExStyle&0x80000)!=0x80000)                SetWindowLong(wndinfo->hWnd,GWL_EXSTYLE,dwExStyle^0x80000);                //SetWindowLong(wndinfo->hWnd,GWL_EXSTYLE,dwExStyle|=0x80000);            BOOL bRet=FALSE;            bRet=UpdateLayeredWindow(wndinfo->hWnd,hdcScreen,&ptWinPos,                &sizeWindow,m_hdcMemory,&ptSrc,0,&m_Blend,2);            DWORD err = GetLastError();            IMEDebug::DebugLog(err);            EndPaint(wndinfo->hWnd, &ps);            graph.ReleaseHDC(m_hdcMemory);            ::ReleaseDC(wndinfo->hWnd,hdcScreen);            hdcScreen=NULL;            ::ReleaseDC(wndinfo->hWnd,hdcTemp);            hdcTemp=NULL;            DeleteDC(m_hdcMemory);            m_hdcMemory = NULL;            DeleteObject(hBitMap);        }    }}

好几天了，没的办法

[解决办法]
UpdateLayeredWindow第二个参数：
hdcDst
[in]
Handle to a device context (DC) for the screen. This handle is obtained by specifying NULL when calling the function. It is used for palette color matching when the window contents are updated. If hdcDst isNULL, the default palette will be used.

If hdcSrc is NULL, hdcDst must be NULL.

难道是这个原因？