显示BITMAP
RECT rect;  GetClientRect(hwnd,&rect);
HDC hdcmem,hdc;
     HBITMAP hbitmap,hbitmapOld;
hdc=GetDC(hwnd); 
hdcmem=CreateCompatibleDC(hdc);
hbitmap=LoadBitmap(hInst,MAKEINTRESOURCE(IDB_BACKGROUND));
    GetObject(MAKEINTRESOURCE(IDB_BACKGROUND),sizeof(HBITMAP),hbitmap);    hbitmapOld=(HBITMAP)SelectObject(hdcmem,hbitmap);
 BitBlt(hdc,0,0,420,500,hdcmem,0,0,SRCCOPY);
SelectObject(hdcmem,hbitmapOld);
DeleteObject(hbitmap);
DeleteDC(hdcmem);
ReleaseDC(hwnd,hdc);
    DeleteDC(hdc);