System.Xml.XmlReader.ReadSubtree C# (CSharp) Method

        public virtual XmlReader ReadSubtree()
        {
            if (NodeType != XmlNodeType.Element)
            {
                throw new InvalidOperationException(SR.Xml_ReadSubtreeNotOnElement);
            }
            return new XmlSubtreeReader(this);
        }

 public void ReadXml(XmlReader reader)
 {
     var elementName = string.Empty;
     while (reader.Read())
     {
         if (reader.NodeType == XmlNodeType.Element)
         {
             elementName = reader.Name;
             switch (elementName)
             {
                 case "TypeAliases":
                     {
                         var subReader = reader.ReadSubtree();
                         var aliases = new List<NetTypeAlias>();
                         while (subReader.ReadToFollowing("TypeAlias"))
                         {
                             var aliasReader = subReader.ReadSubtree();
                             var typeAlias = new NetTypeAlias();
                             typeAlias.ReadXml(aliasReader);
                             aliases.Add(typeAlias);
                         }
                         TypeAliases = aliases.ToArray();
                         break;
                     }
                 case "Snippets":
                     {
                         var subReader = reader.ReadSubtree();
                         var snippets = new List<Snippet>();
                         while (subReader.ReadToFollowing("Snippet"))
                         {
                             var snippet = new Snippet();
                             snippet.ReadXml(subReader);
                             snippets.Add(snippet);
                         }
                         Snippets = snippets.ToArray();
                         break;
                     }
             }
         }
         else if (reader.NodeType == XmlNodeType.Text)
         {
             switch (elementName)
             {
                 case "Modifiers":
                     Modifiers = reader.Value.Split(' ');
                     break;
                 case "MemberIdentifiers":
                     MemberIdentifiers = reader.Value.Split(' ');
                     break;
                 case "Keywords":
                     Keywords = reader.Value.Split(' ');
                     break;
             }
         }
         else if (reader.NodeType == XmlNodeType.EndElement)
         {
             elementName = string.Empty; 
         }
     }
 }