asp.net the difference between dataset.writexml (String) and (Stream) _ Practical Tips

The XML file generated by DataSet.WriteXml (String) contains an XML declaration, while DataSet.WriteXml (Stream) does not write to the XML declaration, which is <?xml version= "1.0" Yes "?>
Detailed information:
When writing a data backup program for a blog park, you would have wanted to pass the DS. WriteXml (Response.outputstream) directly to the XML data sent to the client, but this in the client-made XML file in all Chinese is garbled, garbled XML file and normal XML file is less than a row of XML declaration. Then, I changed the code, manual write XML declaration, garbled problem is resolved, the code is as follows:
XmlTextWriter writer = new XmlTextWriter (Response.outputstream, response.contentencoding);
Writer. formatting = formatting.indented;
Writer. indentation = 4;
Writer. IndentChar = ';
Writer. WriteStartDocument ();
Ds. WriteXml (writer);
Writer. Flush ();
Response.End ();
Writer. Close ();