// using System.IO;
// using System.Xml;
XmlDocument xdoc = new XmlDocument();
xdoc.Load("C:\\Export DataSet_INPUT.xml");
// Now create StringWriter object to get data from xml document.
StringWriter sw = new StringWriter();
XmlTextWriter xw = new XmlTextWriter(sw);
xdoc.WriteTo(xw);
String xmlstring = sw.ToString();