MFC 打开文件夹和文件

CString m_strFilePathName;
CFileDialog dlg(TRUE,NULL,NULL,OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,_T("All Files(*.txt)|*.txt|所有文件(*.*)|*.*|"),NULL);
if (dlg.DoModal())
{
    m_strFilePathName = dlg.GetPathName();
}

char szDir[MAX_PATH];

    BROWSEINFO bi;

    ITEMIDLIST *pidl;

    bi.hwndOwner = this->m_hWnd;

    bi.pidlRoot = NULL;

    bi.pszDisplayName = szDir;

    bi.lpszTitle = "请选择目录";

    bi.ulFlags = BIF_STATUSTEXT | BIF_USENEWUI | BIF_RETURNONLYFSDIRS;

    bi.lpfn = NULL;

    bi.lParam = 0;

    bi.iImage = 0;

    pidl = SHBrowseForFolder(&bi);

    if(pidl == NULL)  return;

    if(!SHGetPathFromIDList(pidl, szDir))