Question

我正在使用MFC类，但使用的是非标准方式（即完全不使用CDocument派生的类）。

尽管如此，我有几个从CFormView派生的视图，并且有类成员变量。

我有使用CMiniFrameWnd派生类的代码，就像这样

CCreateContext context;
context.m_pNewViewClass = RUNTIME_CLASS(CImageView);
context.m_pCurrentDoc = NULL;
CView* pNewView = STATIC_DOWNCAST(CView, CreateView(&context));
if (pNewView != NULL)
{  
    pNewView->ShowWindow(SW_SHOW);
    pNewView->OnInitialUpdate();
    SetActiveView(pNewView);
}
// save view

但是与此类似的是CreateView（）正在调用CImageView的默认构造函数，而OnInitialUpdate（）是一个虚拟重写，必须与CView（）的签名匹配。

那么，如何初始化属于CImageView的成员数据？ CreateView（）和OnInitialUpdate（）会妨碍您的工作（除非我遗漏了一些东西）。似乎在MFC体系结构中不容易初始化CView或CFormView的派生类。

谢谢

Answer 1

我要承认，我不确定这不是您想要的，但是在我的应用程序中，我必须转换为其他视图类型。我是这样的：

BOOL CCommunityTalksDoc::SwitchToView(CRuntimeClass* pNewViewClass)
{
    POSITION        rPos;
    CView           *pOldActiveView;
    CFrameWnd       *pChild;
    CCreateContext  context;
    BOOL            bAutoDelete;

    rPos = GetFirstViewPosition();
    pOldActiveView = GetNextView(rPos);
    pChild = pOldActiveView->GetParentFrame();

    // If we're already displaying this kind of view, no need to go further.
    if (pOldActiveView->IsKindOf(pNewViewClass))
        return TRUE;

    // Set flag so that document will not be deleted when view is destroyed.
    bAutoDelete = m_bAutoDelete;
    m_bAutoDelete = FALSE;
    // Delete existing view
    pOldActiveView->DestroyWindow();
    // restore flag
    m_bAutoDelete = bAutoDelete;

    // Create new view.
    m_pScriptView = (CScriptParseView*)pNewViewClass->CreateObject();
    if (m_pScriptView == nullptr)
    {
        TRACE1("Warning: Dynamic create of view type %s failed\n", pNewViewClass->m_lpszClassName);
        return FALSE;
    }

    // we must ensure the popup dialogues don't display
    m_pScriptView->SetBuildMode(FALSE);

    // Draw new view.
    context.m_pNewViewClass = pNewViewClass;
    context.m_pCurrentDoc = this;
    context.m_pNewDocTemplate = nullptr;
    context.m_pLastView = nullptr;
    context.m_pCurrentFrame = pChild;
    if (!m_pScriptView->Create(nullptr, nullptr, AFX_WS_DEFAULT_VIEW, CRect(0, 0, 0, 0), 
                pChild, AFX_IDW_PANE_FIRST, &context))
    {
        TRACE0("Warning: couldn't create view for frame\n");
        delete m_pScriptView;
        m_pScriptView = nullptr;
        return FALSE; 
    }

    m_pScriptView->SendMessage(WM_INITIALUPDATE, 0, 0);  // WM_INITIALUPDATE is defined in afxpriv.h
    pChild->RecalcLayout();
    m_pScriptView->UpdateWindow();
    pChild->SetActiveView(m_pScriptView);
    return TRUE;
}

呼叫代码：

// we must set our view correctly
// note, I am not convinced we are doing this in the right place
// what happens if user makes a second view?
// and what about when RebuildReport is called ?
if(m_pScriptView == nullptr)
{
    //bNewReport = true;
    // we must create view
    pNewViewClass = RUNTIME_CLASS(CScriptParseView);
    if (!SwitchToView(pNewViewClass))
    {
        // fail, don't know why it would fail
        ASSERT(FALSE);
    }
    else
    {
        // we set the variables map only once
        m_pScriptView->SetVarValuesMap(psData->pMapSSVarsValues);
        m_pScriptView->SetVarOptionsMap(psData->pMapSSVarsOptions); // AJT v10.6.0
    }
}

希望这会有所帮助。

初始化MFC中CFormView派生类的成员数据

1 个答案: