通过System.IO.MemoryStream类来实现。 
  通过System.Text.StringBuilder类来实现。    
  下面是具体的实现方法:    
  System.
xml.Xsl.XslTransform RssXslt = new System.
xml.Xsl.XslTransform(); 
  System.
xml.
xmlDocument Rss
xml = new System.
xml.
xmlDocument(); 
  RssXslt.Load(Server.MapPath("RssReader.xslt")); 
  Rss
xml.Load(Server.MapPath("Rss.
xml")); 
  System.IO.MemoryStream t = new System.IO.MemoryStream(); 
  RssXslt.Transform(Rss
xml,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 Rss
xml = new System.
xml.
xmlDocument(); 
  RssXslt.Load(Server.MapPath("RssReader.xslt")); 
  Rss
xml.Load(Server.MapPath("Rss.
xml")); 
  System.Text.StringBuilder t = new System.Text.StringBuilder(); 
  RssXslt.Transform(Rss
xml,null,new System.IO.StringWriter(t),null); 
  string resultString = t.ToString(); 
  Response.Write(resultString);