C++ 在另一个子窗口的顶部绘制子窗口？

在我的win32应用程序中，我有不同的屏幕用于不同的目的，每个屏幕具有不同的背景。主窗口有自己的静态背景。 我正在使用以下代码在自定义窗口上绘制屏幕背景

panelBackground = LoadBitmap ( hInstance, MAKEINTRESOURCE ( bitmap ) );

WNDCLASSEX wincl;

wincl.hInstance         = hInstance;
wincl.lpszClassName     = "jPanel";
wincl.lpfnWndProc       = WndProc;
wincl.style             = CS_BYTEALIGNWINDOW;// | CS_HREDRAW | CS_VREDRAW;
wincl.cbSize            = sizeof (WNDCLASSEX);
wincl.hIcon             = 0;
wincl.hIconSm           = 0;
wincl.hCursor           = LoadCursor (NULL, IDC_ARROW);
wincl.lpszMenuName      = NULL;
wincl.cbClsExtra        = 0;
wincl.cbWndExtra        = 4;
wincl.hbrBackground     = ( HBRUSH ) GetStockObject( BLACK_BRUSH );

RegisterClassEx (&wincl);

hwnd = CreateWindowEx ( 0, "jPanel", txt.c_str(), WS_CLIPSIBLINGS | WS_CHILD, x, y, width, height, parent, 0, hInstance, 0) ;

SetWindowLong( hwnd , 0 , ( LONG ) this ) ;

SetWindowPos ( hwnd , HWND_BOTTOM, 0, 0, 0, 0, SWP_NOSIZE | SWP_NOMOVE ) ;

然后在WndProc中：

view::jPanel* panel = ( view::jPanel* ) GetWindowLong( hwnd , 0 ) ;

case WM_PAINT:
  {
     if ( ! panel )
        return 0 ;

     HDC hdc ;
     PAINTSTRUCT ps ;
     RECT rect ;

     GetClientRect( hwnd , &rect ) ;

      hdc = BeginPaint( hwnd , &ps ) ;


         HDC dcSkin = CreateCompatibleDC ( hdc );                               // memory dc for skin

         HDC hMemDc = CreateCompatibleDC ( hdc );                               // memory dc for painting


         HBITMAP hmemBmp = CreateCompatibleBitmap ( hdc, rect.right - rect.left, rect.bottom - rect.top  );     // Create bitmap to draw on


         HBITMAP hOldMemBmp = (HBITMAP)SelectObject ( hMemDc, hmemBmp );        // select memory bitmap in memory dc

         HBITMAP hOldSkinBmp = (HBITMAP)SelectObject ( dcSkin, panel->panelBackground );    //select skin bitmap in skin memory dc


            BitBlt ( hMemDc, 0, 0, rect.right - rect.left, rect.bottom - rect.top, dcSkin, 0, 0, SRCCOPY );     // Paint Skin on Memory DC
            BitBlt ( hdc, 0, 0, rect.right - rect.left, rect.bottom - rect.top, hMemDc, 0, 0, SRCCOPY );            // Paint Skin on Window DC


         //<<<... DeleteDC will leak memory if it holds a resource, so lets select the old bitmap back in the memory DCs
         SelectObject ( hMemDc, hOldMemBmp );                                   // select old bitmaps back to their respective DCs before deleting
         SelectObject ( dcSkin, hOldSkinBmp );                                  // select old bitmaps back to their respective DCs before deleting


         DeleteObject ( hOldSkinBmp );
         DeleteObject ( hOldMemBmp );
         DeleteObject(  hmemBmp );
         DeleteDC ( hMemDc );
         DeleteDC ( dcSkin );


      EndPaint( hwnd , &ps ) ;
  }
  break ;

view:：jPanel*面板=（view:：jPanel*）GetWindowLong（hwnd，0）；
案例WM_油漆：
{
如果（！面板）
返回0；
HDC-HDC；
PAINTSTRUCT-ps；
RECT-RECT；
GetClientRect（hwnd和rect）；
hdc=开始喷漆（hwnd和ps）；
HDC dcSkin=CreateCompatibleDC（HDC）；//用于皮肤的内存dc
HDC hMemDc=CreateCompatibleDC（HDC）；//用于绘制的内存dc
HBITMAP hmemBmp=CreateCompatibleBitmap（hdc，rect.right-rect.left，rect.bottom-rect.top）；//创建要绘制的位图
HBITMAP hOldMemBmp=（HBITMAP）SelectObject（hMemDc，hmemBmp）；//在内存dc中选择内存位图
HBITMAP hOldSkinBmp=（HBITMAP）SelectObject（dcSkin，panel->panelBackground）；//在皮肤内存dc中选择皮肤位图
BitBlt（hMemDc，0，0，rect.right-rect.left，rect.bottom-rect.top，dcSkin，0，0，SRCCOPY）；//在内存DC上绘制外观
BitBlt（hdc，0，0，rect.right-rect.left，rect.bottom-rect.top，hMemDc，0，0，SRCCOPY）；//在窗口DC上绘制蒙皮
// 创建父窗口时添加
WS\u CLIPCHILDREN
样式。
是的，屏幕背景窗口不是按钮和编辑的父窗口，它是按钮和编辑的同级窗口，它们的父窗口都具有WS\u CLIPCHILDREN样式。