如何调用通用对话框(2)

如何让通用对话框支持多选:

void C通用对话框Dlg::OnBnClickedButton1()
{
    CFileDialog fileDlg(TRUE,NULL,NULL,OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT|OFN_ALLOWMULTISELECT,_T("Text Files(*.txt)|*.txt|Execute Files(*.exe)|*.exe|WinRAR Files(*.rar)|*rar|ALL Files(*.*)|*.*||"));
    if (fileDlg.DoModal() == IDOK)
    {
        POSITION pos = fileDlg.GetStartPosition();
        while (pos) {
            CString str = fileDlg.GetNextPathName(pos);
            MessageBox(str);
        }
        //SetDlgItemText(IDC_EDIT1, fileDlg.GetPathName());
    }
}