CFrameWnd::GetActiveView函数点滴

最新推荐文章于 2024-05-10 19:10:59 发布

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最新推荐文章于 2024-05-10 19:10:59 发布 · 7k 阅读

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#command #mfc #null #测试

本文探讨了一种在不使用文档视图结构的MFC应用程序中，CMainFrame::OnCmdMsg如何处理WM_COMMAND消息。文章指出CFrameWnd::GetActiveView在非文档视图结构中通常返回NULL，导致消息无法正确传递给视图。作者通过测试发现，必须在CMainFrame::OnCmdMsg中直接调用m_wndView.OnCmdMsg以确保消息传递给视图。作者正寻找更多关于CFrameWnd::GetActiveView的资料以验证其理解，并欢迎读者指正错误。

我用vc6的生成向导生成了一个不使用document/view结构的运用程序。

仔细看了一下他的结构，发现了一个函数如下（摘自mfc源代码）：

BOOL CMainFrame::OnCmdMsg(UINT nID, int nCode, void* pExtra, AFX_CMDHANDLERINFO* pHandlerInfo)
{
// let the view have first crack at the command
if (m_wndView.OnCmdMsg(nID, nCode, pExtra, pHandlerInfo))
{
return TRUE;
}
// otherwise, do default handling
return CFrameWnd::OnCmdMsg(nID, nCode, pExtra, pHandlerInfo);
}

开始的时候，我对这段代码很不理解，因为OnCmdMsg函数是处理WM_COMMAND消息的。参照CFrameWnd::OnCmdMsg,CView::OnCmdMsg,CCmdTarget::OnCmdMsg,CDocument::OnCmdMsg的说明。似乎整个WM_COMMAND消息的流动路线已经被定型了，如下：

(图片摘自vckbase.com)

CFrameWnd::OnCmdMsg函数的部分代码如下：

BOOL CFrameWnd::OnCmdMsg(UINT nID, int nCode, voi

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3 条评论

st251256589a 2011.04.25
完全正解，顶楼主，至少解决了我的问题[e03]

同行小弟 2006.01.18
可以看看MSDN

同行小弟 2006.01.18
CFrameWnd::GetActiveView CView* GetActiveView( ) const; Return Value A pointer to the current CView. If there is no current view, returns NULL. Remarks Call this member function to obtain a pointer to the active view (if any) attached to a frame window (CFrameWnd). This function returns NULL when called for an MDI main frame window (CMDIFrameWnd). In an MDI application, the MDI main frame window does not have a view associated with it. Instead, each individual child window (CMDIChildWnd) has one or more associated views. The active view in an MDI application can be obtained by first finding the active MDI child window and then finding the active view for that child window. The active MDI child window can be found by calling the function MDIGetActive or GetActiveFrame as demonstrated in the following: CMDIFrameWnd *pFrame = (CMDIFrameWnd*)AfxGetApp()->m_pMainWnd; // Get the active MDI child window. CMDIChildWnd *pChild = (CMDIChildWnd *) pFrame->GetActiveFrame(); // or CMDIChildWnd *pChild = pFrame->MDIGetActive(); // Get the active view attached to the active MDI child // window. CMyView *pView = (CMyView *) pChild->GetActiveView();