Old XmlDocument-based Keyreader

KeyReader.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using System.IO;

namespace TechnetKeyReader
{
    public partial class KeyReader : Form
    {
        public KeyReader()
        {
            InitializeComponent();
        }

        private void openDlg(object sender, EventArgs e)
        {
            openXmlDlg.ShowDialog();
            Properties.Settings.Default.lastFile = openXmlDlg.FileName;
            loadXmlFunc(null, null);
        }


        private void loadXmlFunc(object sender, EventArgs e)
        {
            StreamReader readThatXml;
            XmlTextReader parseThatXml;
            XmlDocument thatXmlDoc = new XmlDocument();

            try
            {
                readThatXml = new StreamReader(Properties.Settings.Default.lastFile);
                parseThatXml = new XmlTextReader(readThatXml);
                thatXmlDoc.Load(parseThatXml);
            }
            catch (XmlException XmlEx)
            {
                MessageBox.Show(XmlEx.Message);
            }
            catch (Exception Ex)
            {
                MessageBox.Show(Ex.Message);
            }

            /* Parse Time */
            XmlNodeList productNames = thatXmlDoc.SelectNodes("YourKey/Product_Key");
            int currentNode = 0;
            KeyNode[] KeyGroups = new KeyNode[productNames.Count];


            foreach (XmlNode product in productNames)
            {
                KeyGroups[currentNode] = new KeyNode();
                KeyGroups[currentNode].id = currentNode;
                KeyGroups[currentNode].productName = product.Attributes["Name"].Value;

                XmlNodeList Keys = product.SelectNodes("Key");
                KeyGroups[currentNode].keys = new string[Keys.Count];
                int currentKey = 0;

                foreach (XmlNode key in Keys)
                {
                    KeyGroups[currentNode].keys[currentKey] = key.InnerText;
                    currentKey++;
                }

                currentNode++;
            }

            productTree.Nodes.Clear();
            string newLine = Environment.NewLine;

            foreach (KeyNode keyInfo in KeyGroups)
            {
                productTree.Nodes.Add(keyInfo.id.ToString(), keyInfo.productName);
                foreach (string Key in keyInfo.keys)
                {
                    productTree.Nodes[keyInfo.id.ToString()].Nodes.Add(Key);
                }
            }
        }

        private void copyKey(object sender, EventArgs e)
        {
            if (productTree.SelectedNode.Level == 0)
            {
                Clipboard.SetText(productTree.SelectedNode.Nodes[0].Text);
            }
            else
            {
                Clipboard.SetText(productTree.SelectedNode.Text);
            }
        }

        private void copyName(object sender, EventArgs e)
        {
            if (productTree.SelectedNode.Level == 0)
            {
                Clipboard.SetText(productTree.SelectedNode.Text);
            }
            else
            {
                Clipboard.SetText(productTree.SelectedNode.Parent.Text);
            }
        }

        private void showAbout(object sender, EventArgs e)
        {
            about aboutFrm = new about();
            aboutFrm.Show();
        }
    }
}