How can i compare two xml files contents?

What i need to do is to compare two xml files contents and if there is a different between them write it to a third new xml file.

This is the class where i write and read back the xml files content:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Xml;
using System.Windows.Forms;

namespace FTP_ProgressBar
{
    class TreeViewXmlPopulation
    {
        // Xml tag for node, e.g. 'node' in case of <node></node>
        private const string XmlNodeTag = "node";

        // Xml attributes for node e.g. <node text="Asia" tag="" 
        // imageindex="1"></node>
        private const string XmlNodeTextAtt = "text";
        private const string XmlNodeTagAtt = "tag";
        private const string XmlNodeImageIndexAtt = "imageindex";

        public static void DeserializeTreeView(TreeView treeView, string fileName)
        {
            XmlTextReader reader = null;
            try
            {
                // disabling re-drawing of treeview till all nodes are added
                treeView.BeginUpdate();
                reader = new XmlTextReader(fileName);
                TreeNode parentNode = null;
                while (reader.Read())
                {
                    if (reader.NodeType == XmlNodeType.Element)
                    {
                        if (reader.Name == XmlNodeTag)
                        {
                            TreeNode newNode = new TreeNode();
                            bool isEmptyElement = reader.IsEmptyElement;

                            // loading node attributes
                            int attributeCount = reader.AttributeCount;
                            if (attributeCount > 0)
                            {
                                for (int i = 0; i < attributeCount; i++)
                                {
                                    reader.MoveToAttribute(i);
                                    SetAttributeValue(newNode,
                                                 reader.Name, reader.Value);
                                }
                            }
                            // add new node to Parent Node or TreeView
                            if (parentNode != null)
                                parentNode.Nodes.Add(newNode);
                            else
                                treeView.Nodes.Add(newNode);

                            // making current node 'ParentNode' if its not empty
                            if (!isEmptyElement)
                            {
                                parentNode = newNode;
                            }
                        }
                    }
                    // moving up to in TreeView if end tag is encountered
                    else if (reader.NodeType == XmlNodeType.EndElement)
                    {
                        if (reader.Name == XmlNodeTag)
                        {
                            parentNode = parentNode.Parent;
                        }
                    }
                    else if (reader.NodeType == XmlNodeType.XmlDeclaration)
                    {
                        //Ignore Xml Declaration                    
                    }
                    else if (reader.NodeType == XmlNodeType.None)
                    {
                        return;
                    }
                    else if (reader.NodeType == XmlNodeType.Text)
                    {
                        parentNode.Nodes.Add(reader.Value);
                    }

                }
            }
            finally
            {
                // enabling redrawing of treeview after all nodes are added
                treeView.EndUpdate();
                reader.Close();
            }
        }

        /// <span class="code-SummaryComment"><summary>
        /// Used by Deserialize method for setting properties of 
        /// TreeNode from xml node attributes
        /// <span class="code-SummaryComment"></summary>
        private static void SetAttributeValue(TreeNode node,
                           string propertyName, string value)
        {
            if (propertyName == XmlNodeTextAtt)
            {
                node.Text = value;
            }
            else if (propertyName == XmlNodeImageIndexAtt)
            {
                node.ImageIndex = int.Parse(value);
            }
            else if (propertyName == XmlNodeTagAtt)
            {
                node.Tag = value;
            }
        }

        public static void SerializeTreeView(TreeView treeView, string fileName)
        {
            XmlTextWriter textWriter = new XmlTextWriter(fileName,
                                          System.Text.Encoding.ASCII);
            // writing the xml declaration tag
            textWriter.WriteStartDocument();
            //textWriter.WriteRaw("\r\n");
            // writing the main tag that encloses all node tags
            textWriter.WriteStartElement("TreeView");

            // save the nodes, recursive method
            SaveNodes(treeView.Nodes, textWriter);

            textWriter.WriteEndElement();

            textWriter.Close();
        }

        private static void SaveNodes(TreeNodeCollection nodesCollection,
   XmlTextWriter textWriter)
        {
            for (int i = 0; i < nodesCollection.Count; i++)
            {
                TreeNode node = nodesCollection[i];
                textWriter.WriteStartElement(XmlNodeTag);
                textWriter.WriteAttributeString(XmlNodeTextAtt,
                                                           node.Text);
                textWriter.WriteAttributeString(
                    XmlNodeImageIndexAtt, node.ImageIndex.ToString());
                if (node.Tag != null)
                    textWriter.WriteAttributeString(XmlNodeTagAtt,
                                                node.Tag.ToString());
                // add other node properties to serialize here  
                if (node.Nodes.Count > 0)
                {
                    SaveNodes(node.Nodes, textWriter);
                }
                textWriter.WriteEndElement();
            }
        }
    }
}

The method DeserializeTreeView for reading and the method SerializeTreeView for writing.

This is how i use it in a method creating one xml file:

TreeViewXmlPopulation.SerializeTreeView(treeViewMS1, @"c:\XmlFile\Original.xml");

And once in a backgroundworker completed event:

TreeViewXmlPopulation.SerializeTreeView(treeViewMS1, @"c:\XmlFile\New.xml");

In the backgroundworkercompleted event after creating the New.xml file i need somehow to call a new method that will get the two xml files Original and New and compare the content of the two files.

If no difference do nothing if there is a difference then write the difference only into a new third xml file for example : TreeViewXmlPopulation.SerializeTreeView(treeViewMS1, @"c:\XmlFile\Diff.xml");