关于对话框中用listbox显示txt内容的有关问题

void CReadTxtDlg::OnBnClickedButton1()
{
CFileDialog FileDlg(true, _T("txt"),    NULL,  OFN_FILEMUSTEXIST|OFN_HIDEREADONLY,      
                    "文本文件     (*.TXT)|*.TXT|All Files(*.*)|*.*||");      
if( FileDlg.DoModal() == IDOK ) 
{              
    CString fileName;    
fileName = FileDlg.GetFileName();           
CStdioFile file;             
file.Open(fileName,CFile::modeRead,0);           
CListBox *pList = (CListBox *)GetDlgItem(IDC_EDIT);            
pList->ResetContent();               
CString str;        
while(file.ReadString(str)) 
{                         
    pList->AddString(str);              
}            
file.Close();          }
    // TODO: 在此添加控件通知处理程序代码
}