System.Xml.Xsl.XslTransform RssXslt = new System.Xml.Xsl.XslTransform(); 
System.Xml.XmlDocument RssXml = new System.Xml.XmlDocument(); 
RssXslt.Load(Server.MapPath("RssReader.xslt")); 
RssXml.Load(Server.MapPath("Rss.xml")); 
System.IO.MemoryStream t = new System.IO.MemoryStream(); 
RssXslt.Transform(RssXml,null,t,null); 
string resultString = System.Text.UTF8Encoding.UTF8.GetString(t.ToArray()); 
Response.Write(resultString); 

System.Xml.Xsl.XslTransform RssXslt = new System.Xml.Xsl.XslTransform(); 
System.Xml.XmlDocument RssXml = new System.Xml.XmlDocument(); 
RssXslt.Load(Server.MapPath("RssReader.xslt")); 
RssXml.Load(Server.MapPath("Rss.xml")); 
System.Text.StringBuilder t = new System.Text.StringBuilder(); 
RssXslt.Transform(RssXml,null,new System.IO.StringWriter(t),null); 
string resultString = t.ToString(); 
Response.Write(resultString);