学步园

由于自定义控件Custom control需要进行类绑定，只有注册窗口类后才能显示窗口。因此一般定义自定义控件对象后，在构造函数中用AfxRegisterClass注册窗口类，而AfxRegisterClass并不激活WM_CREATE消息，也就是说不能响应到OnCreate函数。那怎么响应OnCreate呢？
替代办法：OnCreate的内容可以用PreSubclassWindow代替。

COpenGLControl::COpenGLControl()<br /> {<br /> RegisterWndClass();<br /> }<br /> BOOL COpenGLControl::RegisterWndClass()<br /> {<br /> WNDCLASS windowclass;<br /> HINSTANCE hInst = AfxGetInstanceHandle();<br /> if (!(::GetClassInfo(hInst, MYWNDCLASS, &windowclass)))<br /> {<br /> windowclass.style = CS_DBLCLKS;// | CS_HREDRAW | CS_VREDRAW;<br /> windowclass.lpfnWndProc = ::DefWindowProc;<br /> windowclass.cbClsExtra = windowclass.cbWndExtra = 0;<br /> windowclass.hInstance = hInst;<br /> windowclass.hIcon = NULL;<br /> windowclass.hCursor = AfxGetApp()->LoadStandardCursor(IDC_ARROW);<br /> windowclass.hbrBackground = ::GetSysColorBrush(COLOR_WINDOW);<br /> windowclass.lpszMenuName = NULL;<br /> windowclass.lpszClassName = MYWNDCLASS;<br /> if (!AfxRegisterClass(&windowclass))<br /> {<br /> AfxThrowResourceException();<br /> return FALSE;<br /> }<br /> }<br /> return TRUE;<br /> }<br /> void COpenGLControl::PreSubclassWindow()<br /> {<br /> CDialog::PreSubclassWindow();<br /> dc = new CClientDC(this);<br /> CRect rc;<br /> GetClientRect(&rc);<br /> openGLDevice.create(dc->m_hDC);<br /> ShowWindow(SW_SHOW);<br /> SetForegroundWindow();<br /> SetFocus();<br /> ReSizeGLScene(rc.Width(),rc.Height());<br /> InitGL();<br /> }

当然，如果不用自定义控件Custom control，而采用类似第三方控件一样，通过void COpenGLControl::Create(CRect rect, CWnd *parent)再调用CreateEx创建窗口，则会激活WM_CREATE消息。

void COpenGLControl::Create(CRect rect, CWnd *parent)<br /> {<br /> CString className = AfxRegisterWndClass(<br /> CS_HREDRAW | CS_VREDRAW | CS_OWNDC,<br /> NULL,<br /> (HBRUSH)GetStockObject(BLACK_BRUSH),<br /> NULL);<br /> CreateEx(<br /> 0,<br /> className,<br /> "OpenGL",<br /> WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,<br /> rect,<br /> parent,<br /> 0);</p> <p>}<br /> int COpenGLControl::OnCreate(LPCREATESTRUCT lpCreateStruct)<br /> {<br /> if (CWnd::OnCreate(lpCreateStruct) == -1)<br /> return -1;<br /> dc = new CClientDC(this);<br /> openGLDevice.create(dc->m_hDC);<br /> ShowWindow(SW_SHOW);<br /> SetForegroundWindow();<br /> SetFocus();<br /> ReSizeGLScene(lpCreateStruct->cx, lpCreateStruct->cy);<br /> InitGL();<br /> return 0;<br /> }