public string TransformXML(string xml, string xslt)
{
  string output = string.Empty;

  XPathDocument xpd = new XPathDocument(new StringReader(xml)); 
            
  XslCompiledTransform transform = new XslCompiledTransform(true);
  transform.Load(new XmlTextReader(xslt, XmlNodeType.Document, null)); 
           
  StringWriter sr = new StringWriter();
  transform.Transform(xpd.CreateNavigator(), null, sr);
  output = sr.ToString(); 
            
  return output; 
}


//Note that the XSL needs namespace prefixes to make .Net happy: 

xsl = @"<xsl:stylesheet version='1.0' 
                        xmlns:xsl='http://www.w3.org/1999/XSL/Transform'>
          <xsl:output method='text'/> 
          <xsl:template match='msg'>Found it!</xsl:template>
        </xsl:stylesheet>";


xml = @"<msg/>";

Minimalist XSLT Transform Using Two Strings

xml, c

C#