gistfile1.cs

public static string EscapeXml( this string s )
    {
      string xml = s;
      if ( !string.IsNullOrEmpty( xml ) )
      {
        // replace literal values with entities
        xml = xml.Replace( "&", "&" );
        xml = xml.Replace( "<", "<" );
        xml = xml.Replace( ">", ">" );
        xml = xml.Replace( "\"", """ );
        xml = xml.Replace( "'", "'" );
      }
      return xml;
    }

    public static string UnescapeXml( this string s )
    {
      string unxml = s;
      if ( !string.IsNullOrEmpty( unxml ) )
      {
        // replace entities with literal values
        unxml = unxml.Replace( "'", "'" );
        unxml = unxml.Replace( """, "\"" );
        unxml = unxml.Replace( ">", ">" );
        unxml = unxml.Replace( "<", "<" );
        unxml = unxml.Replace( "&", "&" );
      }
      return unxml;
    }