Question

使用VS6我注意到在CDateTimeCtrl对象中更改日期时，我的某些对话框会崩溃。调查结果显示，对DDX_DateTimeCtrl的调用将12个字节的数据移动到4个字节宽的CTime对象上。谁能解释为什么会发生这种情况？有谁知道如何纠正它？

部首：

#if !defined(AFX_DATEDIALOG_H__B9373304_D774_4447_A4D1_BB4E1FB3404F__INCLUDED_)
#define AFX_DATEDIALOG_H__B9373304_D774_4447_A4D1_BB4E1FB3404F__INCLUDED_

#if _MSC_VER > 1000
#pragma once
#endif // _MSC_VER > 1000
// DateDialog.h : header file
//

/////////////////////////////////////////////////////////////////////////////
// CDateDialog dialog

class CDateDialog : public CDialog
{
// Construction
public:
    CDateDialog(CWnd* pParent = NULL);   // standard constructor

// Dialog Data
    //{{AFX_DATA(CDateDialog)
    enum { IDD = IDD_DIALOG_DATE };
    CDateTimeCtrl   m_StartDate;
    CDateTimeCtrl   m_EndDate;
    CTime   m_tmEndDate;
    CTime   m_tmStartDate;
    //}}AFX_DATA


// Overrides
    // ClassWizard generated virtual function overrides
    //{{AFX_VIRTUAL(CDateDialog)
    protected:
    virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support
    //}}AFX_VIRTUAL

// Implementation
protected:

    // Generated message map functions
    //{{AFX_MSG(CDateDialog)
    afx_msg void OnButtonBack();
    afx_msg void OnDatetimechangeEndDate(NMHDR* pNMHDR, LRESULT* pResult);
    afx_msg void OnDatetimechangeStartDate(NMHDR* pNMHDR, LRESULT* pResult);
    afx_msg void OnCloseupStartDate(NMHDR* pNMHDR, LRESULT* pResult);
    afx_msg void OnCloseupEndDate(NMHDR* pNMHDR, LRESULT* pResult);
    //}}AFX_MSG
    DECLARE_MESSAGE_MAP()
private:
    // the range limits for the dates; these are set to the values found
    // in m_tmStartDate and m_tmEndDate in OnInitDialog
    CTime m_tmStart;            // beginning of the range
    CTime m_tmEnd;              // end of the range
};

//{{AFX_INSERT_LOCATION}}
// Microsoft Visual C++ will insert additional declarations immediately before the previous line.

#endif // !defined(AFX_DATEDIALOG_H__B9373304_D774_4447_A4D1_BB4E1FB3404F__INCLUDED_)

Code:

// DateDialog.cpp : implementation file
//

#include "stdafx.h"
#include "CustomerSales.h"
#include "DateDialog.h"

#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif

/////////////////////////////////////////////////////////////////////////////
// CDateDialog dialog


CDateDialog::CDateDialog(CWnd* pParent /*=NULL*/)
    : CDialog(CDateDialog::IDD, pParent)
{
    //{{AFX_DATA_INIT(CDateDialog)
    m_tmEndDate = 0;
    m_tmStartDate = 0;
    //}}AFX_DATA_INIT
}


void CDateDialog::DoDataExchange(CDataExchange* pDX)
{
    CDialog::DoDataExchange(pDX);
    //{{AFX_DATA_MAP(CDateDialog)
    DDX_Control(pDX, IDC_START_DATE, m_StartDate);
    DDX_Control(pDX, IDC_END_DATE, m_EndDate);
    DDX_DateTimeCtrl(pDX, IDC_END_DATE, m_tmEndDate);
    DDX_DateTimeCtrl(pDX, IDC_START_DATE, m_tmStartDate);
    //}}AFX_DATA_MAP
}


BEGIN_MESSAGE_MAP(CDateDialog, CDialog)
    //{{AFX_MSG_MAP(CDateDialog)
    ON_BN_CLICKED(IDC_BUTTON_BACK, OnButtonBack)
    ON_NOTIFY(DTN_DATETIMECHANGE, IDC_END_DATE, OnDatetimechangeEndDate)
    ON_NOTIFY(DTN_DATETIMECHANGE, IDC_START_DATE, OnDatetimechangeStartDate)
    ON_NOTIFY(DTN_CLOSEUP, IDC_START_DATE, OnCloseupStartDate)
    ON_NOTIFY(DTN_CLOSEUP, IDC_END_DATE, OnCloseupEndDate)
    //}}AFX_MSG_MAP
END_MESSAGE_MAP()

/////////////////////////////////////////////////////////////////////////////
// CDateDialog message handlers

void CDateDialog::OnButtonBack() 
{
    // exit with our buton ID
    EndDialog(IDC_BUTTON_BACK);
}

void CDateDialog::OnDatetimechangeEndDate(NMHDR* pNMHDR, LRESULT* pResult) 
{
    if(m_EndDate.GetMonthCalCtrl() == NULL)
    {
        UpdateData();

        if(m_tmStartDate > m_tmEndDate)
            m_tmStartDate = m_tmEndDate;

        UpdateData(FALSE);
    }

    *pResult = 0;
}

void CDateDialog::OnDatetimechangeStartDate(NMHDR* pNMHDR, LRESULT* pResult) 
{
    if(m_StartDate.GetMonthCalCtrl() == NULL)
    {
        UpdateData();

        if(m_tmEndDate < m_tmStartDate)
            m_tmEndDate = m_tmStartDate;

        UpdateData(FALSE);
    }

    *pResult = 0;
}

void CDateDialog::OnCloseupStartDate(NMHDR* pNMHDR, LRESULT* pResult) 
{
    UpdateData();

    if(m_tmEndDate < m_tmStartDate)
        m_tmEndDate = m_tmStartDate;

    UpdateData(FALSE);

    *pResult = 0;
}

void CDateDialog::OnCloseupEndDate(NMHDR* pNMHDR, LRESULT* pResult) 
{
    UpdateData();

    if(m_tmStartDate > m_tmEndDate)
        m_tmStartDate = m_tmEndDate;

    UpdateData(FALSE);

    *pResult = 0;
}

Answer 1

很久以前我已经观察过CDateTimeCtrl的错误。如果与CTime变量一起使用，该类的GetTime方法将崩溃。我记得当时我在互联网上找到了与此问题相关的参考资料。我现在找不到它。建议的解决方案是使用COleDateTime。

似乎DDE / DDX交换存在类似的问题，并且最新的MFC中尚未修复它。

当时对我来说最简单的解决方法是使用COleDateTime变量。

DDX_DateTimeCtrl适用于CTime和COleDateTime，因此您的解决方案是使用COleDateTime作为m_tmEndDate和m_tmStartDate变量。

在VC ++ 6中将数据从CDateTimeCtrl移动到CTime对象

1 个答案: