c#保存textbox中的字符串到txt文件中

/********************** 保存接收按钮 *****************************/
        private void SavetxData_Click(object sender, EventArgs e)
        {
            SaveFileDialog saveFileDialog = new SaveFileDialog();
            saveFileDialog.Filter = "(*.txt)|*.txt|(*.*)|*.*";
            saveFileDialog.FileName = "文件" + DateTime.Now.ToString("yyyyMMddHHmm") + ".txt";
            //将日期时间作为文件名
            if (saveFileDialog.ShowDialog() == DialogResult.OK)
            {
                StreamWriter streamWriter = new StreamWriter(saveFileDialog.FileName, true);
                streamWriter.Write(this.rxtextBox.Text);
                streamWriter.Close();
            }
        }