C# 将XmlDocument转化为string

/// <summary>
///
/// 将XmlDocument转化为string
/// /// </summary>
/// /// <param name="xmlDoc"></param>
/// /// <returns></returns>
public string ConvertXmlToString(XmlDocument xmlDoc)
{
MemoryStream stream = new MemoryStream();
XmlTextWriter writer = new XmlTextWriter(stream, null);
writer.Formatting = Formatting.Indented; xmlDoc.Save(writer);
StreamReader sr = new StreamReader(stream, System.Text.Encoding.UTF8);
stream.Position = 0;
string xmlString = sr.ReadToEnd();
sr.Close();
stream.Close();
return xmlString;
}