asp.net从TextBox控件中写入到txt文本

Code
//从testbox中写入到txt文本
        PRotected void Button5_Click(object sender, EventArgs e)
        {
            string text = txtContent.Text;
            if (!string.IsNullOrEmpty(text))
            {
                //指定文件的完整路径
                string fileName = Server.MapPath("~/txt/test.txt");
                //判断该文件是否存在
                if (File.Exists(fileName))
                {
                    //如果存在，就先删掉
                    File.Delete(fileName);
                }
                else
                {
                    //创建一个文件操作的流
                    FileStream stream = new FileStream(fileName, FileMode.Create);
                    //创建一个写操作流
                    StreamWriter writer = new StreamWriter(stream, Encoding.UTF8);
                    //进行写操作
                    writer.Write(text);
                    //清空控件中的文字
                    txtContent.Text = string.Empty;
                    //关闭流，不然出现异常
                    writer.Close();
                    stream.Close();
                }
            }
            else
            {
                Response.Write("<script>alert(\"空的列！\")</script>");
            }
        }

然后再从生成的test.txt中读取数据，显示到TextBox控件中（方法同理）

Code
//读取文本到textbox中显示
        protected void Button6_Click(object sender, EventArgs e)
        {
            string fileName = Server.MapPath("~/txt/test.txt");
            if (File.Exists(fileName))
            {
                FileStream stream = new FileStream(fileName, FileMode.Open);
                StreamReader reader = new StreamReader(stream, Encoding.UTF8);
                txtContent.Text = reader.ReadToEnd();
                reader.Close();
                stream.Close();
            }
            else
            {
                Response.Write("<script>alert(\"没有test.txt文件！\")</script>");
            }
        }