asp.net如何使用DataSet的ReadXml读取XML文件及Stream流

string strxml = "<xml><m><a>1</a><b>2</b></m><m><a>11</a><b>22</b></m><m><a>111</a><b>222</b></m></xml>";
DataSet ds = new DataSet();
Stream stream = new MemoryStream(Encoding.Default.GetBytes(strxml));
ds.ReadXml(stream);
GridView1.DataSource = ds;
GridView1.DataBind();

protected void Page_Load(object sender, EventArgs e)
{
  if (!IsPostBack)
  {
    DataSet ds = new DataSet();
    TextReader reader = new StringReader(@"
          <music>
           <song>
            <artist>The Chi-lites</artist>
            <genre>Soul</genre>
            <album>A lonely man</album>
            <year>1972</year>
           </song>
           <song>
            <artist>Babyface</artist>
            <genre>R&B</genre>
            <album>unknown</album>
            <year></year>
           </song>
           <song>
            <artist>Babyface</artist>
            <genre>R&B</genre>
            <album>The essential babyface</album>
            <year>2001</year>
           </song>
           <song>
            <artist>Babyface</artist>
            <genre>R&B</genre>
            <album>Grown and sexy</album>
            <year>2005</year>
           </song>
           <song>
            <artist>Maria Arredondo</artist>
            <genre>Pop</genre>
            <album>Not going under</album>
            <year>2004</year>
           </song>
           <song>
            <artist>Leona Lewis</artist>
            <genre>Pop</genre>
            <album>Unknown</album>
            <year>2008</year>
           </song>
           <song>
            <artist>Usher</artist>
            <genre>R&B</genre>
            <album>Usher</album>
            <year>2008</year>
           </song>
           <song>
            <artist>Christina Aguilera</artist>
            <genre>Blues</genre>
            <album>Back to basics</album>
            <year>2004</year>
           </song>
           <song>
            <artist>Sting</artist>
            <genre>Pop</genre>
            <album>Shape of my heart</album>
            <year></year>
           </song>
          </music>
          ");
    //读取Xml字符串 用来接收WebService返回数据
    ds.ReadXml(reader, XmlReadMode.Auto);
    //生成Xml文件
    //ds.WriteXml(Server.MapPath("xml/song_bak.xml"));
    GridView1.DataSource = ds;
    GridView1.DataBind();
  }
}

#region 接口返回的Xml转换成DataSet
/// <summary>
/// 返回的Xml转换成DataSet
/// </summary>
/// <param name="text">Xml字符</param>
/// <returns></returns>
private DataSet GetDataSet(string text)
{
  try
  {
    XmlTextReader reader = new XmlTextReader(new StringReader(text));
    reader.WhitespaceHandling = WhitespaceHandling.None;
    DataSet ds = new DataSet();
    ds.ReadXml(reader);
    reader.Close();
    ds.Dispose();
    return ds;
  }
  catch
  {
    return null;
  }
}
#endregion
#region 后台提交数据且获取接口返回的数据
/// <summary>
/// 后台提交数据且获取接口返回的数据
/// </summary>
/// <param name="relativePath">地址</param>
/// <returns></returns>
public static string GetRequestString(string relativePath)
{
  string requestUrl = relativePath;
  try
  {
    // 创建一个HTTP请求
    HttpWebRequest request = (System.Net.HttpWebRequest)WebRequest.Create(requestUrl);
    request.Method = "GET";
    StreamReader jsonStream = new StreamReader(request.GetResponse().GetResponseStream());
    string jsonObject = jsonStream.ReadToEnd();
    return jsonObject;
  }
  catch
  {
    return string.Empty;
  }
}
#endregion