VS找到工程文件的路径，并遍历此路径下的所有 .txt文件

【代码文件】：在OnBnClickedButtonLoad按钮控件下输入如下代码：

char szFileName[MAX_PATH]
m_strDataDir = szFileName;
        auto nDirPos = m_strDataDir.ReverseFind('\\');//ReverseFine从后向前查找"\\"符号
            if (std::string::npos == nDirPos)
            m_strDataDir = "";
        else
            m_strDataDir.Truncate(nDirPos + 1);

在 .h文件中添加 

protected:

    CString m_strDataDir
    

在PreTranslateMessage(MSG* pMsg)下，添加如下代码，可使用上下按键切换路径下的 .txt文件

BOOL CdialogpaintDlg::PreTranslateMessage(MSG* pMsg)
{ 
    if ((m_nJusyOpenedfile == 1) && (pMsg->message == WM_KEYDOWN) && ((pMsg->wParam == VK_UP) || (pMsg->wParam == VK_DOWN)))
    {
        m_nFilesCount = 0;
        CString strFile;
        CFileFind find;
        //=====================================================================================
        CString strFindStr;
        strFindStr = m_strDataDir;
        strFindStr += _T("*.txt");
        BOOL bWorking = find.FindFile(strFindStr);
        //=====================================================================================

        //BOOL bWorking = find.FindFile(_T("E:/vs2019/project2019/dialog_paint/*.txt"));
        m_filelist.clear();
        while (bWorking)
        {
            bWorking = find.FindNextFile();//开始遍历
            strFile = find.GetFileName();
            m_filelist.push_back(strFile);
            m_nFilesCount++;
            //OnBnClickedButtonLoad();
            //遍历第一个跳到读取文件内容
        }find.Close();//遍历文件夹所有txt文件,并存到strFile中

        m_nJusyOpenedfile = 0;
    }

    //*******************************************************************************************
    CString Memory;
    int k = 0;
    int num = 0;
    LPCTSTR p=NULL;

    char buf[MAX_LINE] = { 0 };  
    do
    {
        if (pMsg->message == WM_KEYDOWN)
        {
            int need_refresh = 0;
            if (pMsg->wParam == VK_UP)
            {
                if (m_index_in_list > 0)

                {
                    m_index_in_list--; need_refresh = 1;
                }
                else
                {
                    Beep(400, 200); break;
                }
            }
            else if (pMsg->wParam == VK_DOWN)
            {
                if (m_index_in_list < m_nFilesCount - 1)
                {
                    m_index_in_list++; need_refresh = 1;
                }
                else
                {
                    Beep(400, 200); break;
                }
            }

            if (need_refresh)
            {
                char szFilename[1024] = { 0 };
                CString str = m_filelist.at(m_index_in_list);
                SHUnicodeToAnsi(str.GetString(), szFilename, MAX_PATH);
                deal_with_a_full_paht_name_file(szFilename);
            }
        }//find.Close();
    } while (0);

    return CDialogEx::PreTranslateMessage(pMsg);
}