bsp;  return 0;

---- 3) 对OnDestroy函数修改：

   void CTestmdiView::OnDestroy()
   {
   // 确保删除的是正确的视图及其绘制上下文
   wglMakeCurrent(m_pCDC- >GetSafeHdc(), m_hRC);
   if (m_hRC!=NULL)
   ::wglDeleteContext(m_hRC);

   // destroy Win Device Context
if(m_pCDC)
   delete m_pCDC;

    ..
   //Todo: ..
   }

---- 4)OnDraw()函数做如下修改：

   void CTestmdiView::OnDraw()
   {
   ..
   //Todo: .
   wglMakeCurrent(m_pCDC- >GetSafeHdc(), m_hRC);

   if   (pApp- >m_iCount%2==0)
   {
   //第偶数个视图， 画正方形
   DrawSquare();
   }
   else
   {
   //第奇数个视图，画圆
   DrawCircle();
   }
   
   //注意画完之后立即断开DC与RC的关联，
使其他视图在激活时能正确与RC相联
   wglMakeCurrent(NULL, NULL);   
   }

---- 5)PreCreateWindow(CREATESTRUCT &cs)函数：

   BOOL CTestmdiView::PreCreateWindow(CREATESTRUCT& cs)
   {
   // TODO: Modify the Window
   class or styles here by modifying
   //  the CREATESTRUCT cs

   //  OpenGL的要求：
   cs.style |= WS_CLIPSIBLINGS | WS_CLIPCHILDREN;

   //  MDI 应用的要求：
   cs.lpszClass = AfxRegisterWndClass(CS_OWNDC |
CS_HREDRAW | CS_VREDRAW);

   return CView::PreCreateWindow(cs);
   }