JavaScript Error

// Copyright 2024 T&J Divisions, LLC	
// All Rights Reserved
using System.Collections;
using System.Windows.Forms;

namespace TestProgram
{
    public partial class Form1 : Form
    {
        private ListViewColumnSorter lvwColumnSorter;

        public Form1()
        {
            InitializeComponent();

            // Create an instance of a ListView column sorter and assign it to the ListView control.
            lvwColumnSorter = new ListViewColumnSorter();
            this.listView1.ListViewItemSorter = lvwColumnSorter;
        }

        void Form1_Load(object sender, EventArgs e)
        {
            // add item #1 to the listview
            ListViewItem newItem1 = new ListViewItem();
            newItem1.Text = "Moderator";
            newItem1.SubItems.Add("Bruce");
            newItem1.SubItems.Add("Wayne");
            listView1.Items.Add(newItem1);

            // add item #2 to the listview
            ListViewItem newItem2 = new ListViewItem();
            newItem2.Text = "Guest";
            newItem2.SubItems.Add("Barry");
            newItem2.SubItems.Add("Allen");
            listView1.Items.Add(newItem2);

            // resize the columns
            resizeColumns();
        }

        private void resizeColumns()
        {
            // Loop through and set each column header width to -2 so that the column will auto-size itself to fit the cell contents.
            foreach (ColumnHeader ch in this.listView1.Columns)
            {
                ch.Width = -2;
            }
        }

        private void listView1_ColumnClick(object sender, ColumnClickEventArgs e)
        {
            // precheck to ensure it has more than 1 item to sort
            if(listView1.Items.Count <= 1) { return; }

            // Determine if clicked column is already the column that is being sorted.
            if (e.Column == lvwColumnSorter.SortColumn)
            {
                // Reverse the current sort direction for this column.
                if (lvwColumnSorter.Order == SortOrder.Ascending)
                {
                    lvwColumnSorter.Order = SortOrder.Descending;
                }
                else
                {
                    lvwColumnSorter.Order = SortOrder.Ascending;
                }
            }
            else
            {
                // Set the column number that is to be sorted; default to ascending.
                lvwColumnSorter.SortColumn = e.Column;
                lvwColumnSorter.Order = SortOrder.Ascending;
            }

            // Perform the sort with these new sort options.
            this.listView1.Sort();
        }

        private void listView1_SelectedIndexChanged(object sender, EventArgs e)
        {
            // init default values
            string title = "";
            string firstName = "";
            string lastName = "";

            // get the values of the selected record
            if(listView1.SelectedItems != null && listView1.SelectedItems.Count > 0)
            {
                title = listView1.SelectedItems[0].SubItems[0].Text;
                firstName = listView1.SelectedItems[0].SubItems[1].Text;
                lastName = listView1.SelectedItems[0].SubItems[2].Text;
            }

            // display them in the Records group box controls
            int itemIndex = cbTitle.Items.IndexOf(title);
            cbTitle.SelectedIndex = itemIndex;
            tbFirstName.Text = firstName;
            tbLastName.Text = lastName;
        }

        private void buttonNew_Click(object sender, EventArgs e)
        {
            // precheck for values
            if(tbFirstName.Text.Trim() == "" && tbLastName.Text.Trim() == "")
            {
                MessageBox.Show(this, "Blank or empty name is not allowed", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            // instantiate an instance of a new ListViewItem
            ListViewItem newItem = new ListViewItem();

            // set item the values
            newItem.Text = cbTitle.Text;
            newItem.SubItems.Add(tbFirstName.Text);
            newItem.SubItems.Add(tbLastName.Text);

            // add the item to the listview
            listView1.Items.Add(newItem);

            // select just this item in the listview
            listView1.SelectedItems.Clear();
            newItem.Selected = true;

            // resize the columns to auto-fit
            resizeColumns();

        }

        private void buttonUpdate_Click(object sender, EventArgs e)
        {
            // precheck to ensure something is selected
            if (listView1.SelectedItems == null || listView1.SelectedItems.Count == 0)
            {
                MessageBox.Show(this, "You must first select an item to edit", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            // precheck for values
            if (tbFirstName.Text.Trim() == "" && tbLastName.Text.Trim() == "")
            {
                MessageBox.Show(this, "Blank or empty name is not allowed", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            // get index of selected item
            int itemIndex = listView1.SelectedItems[0].Index;

            // update the selected item
            listView1.Items[itemIndex].SubItems[0].Text = cbTitle.Text;
            listView1.Items[itemIndex].SubItems[1].Text = tbFirstName.Text;
            listView1.Items[itemIndex].SubItems[2].Text = tbLastName.Text;

            // resize the columns to auto-fit
            resizeColumns();
        }

        private void buttonDelete_Click(object sender, EventArgs e)
        {
            // precheck to ensure something is selected
            if (listView1.SelectedItems == null || listView1.SelectedItems.Count == 0)
            {
                MessageBox.Show(this, "You must first select an item to delete", "Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                return;
            }

            // get index of selected item
            int itemIndex = listView1.SelectedItems[0].Index;

            // remove the item at the specified index
            listView1.Items.RemoveAt(itemIndex);

            // resize the columns to auto-fit
            resizeColumns();
        }

    }


    /// <summary>
    /// This class is an implementation of the 'IComparer' interface,
    /// which we are using to sort the ListView by column.
    /// </summary>
    public class ListViewColumnSorter : IComparer
    {
        // Specifies the column to be sorted
        private int ColumnToSort;

        // Specifies the order in which to sort (i.e. 'Ascending').
        private SortOrder OrderOfSort;

        // Case insensitive comparer object
        private CaseInsensitiveComparer ObjectCompare;

        // Class constructor. Initializes various elements
        public ListViewColumnSorter()
        {
            // Initialize the column to '0'
            ColumnToSort = 0;

            // Initialize the sort order to 'none'
            OrderOfSort = SortOrder.None;

            // Initialize the CaseInsensitiveComparer object
            ObjectCompare = new CaseInsensitiveComparer();
        }

        /// <summary>
        /// This method is inherited from the IComparer interface. It compares the two objects passed using a case insensitive comparison.
        /// </summary>
        /// <param name="x">First object to be compared</param>
        /// <param name="y">Second object to be compared</param>
        /// <returns>The result of the comparison. "0" if equal, negative if 'x' is less than 'y' and positive if 'x' is greater than 'y'</returns>
        public int Compare(object x, object y)
        {
            int compareResult;
            ListViewItem listviewX, listviewY;

            // Cast the objects to be compared to ListViewItem objects
            listviewX = (ListViewItem)x;
            listviewY = (ListViewItem)y;

            // Compare the two items
            compareResult = ObjectCompare.Compare(listviewX.SubItems[ColumnToSort].Text, listviewY.SubItems[ColumnToSort].Text);

            // Calculate correct return value based on object comparison
            if (OrderOfSort == SortOrder.Ascending)
            {
                // Ascending sort is selected, return normal result of compare operation
                return compareResult;
            }
            else if (OrderOfSort == SortOrder.Descending)
            {
                // Descending sort is selected, return negative result of compare operation
                return (-compareResult);
            }
            else
            {
                // Return '0' to indicate they are equal
                return 0;
            }
        }

        /// <summary>
        /// Gets or sets the number of the column to which to apply the sorting operation (Defaults to '0').
        /// </summary>
        public int SortColumn
        {
            set
            {
                ColumnToSort = value;
            }
            get
            {
                return ColumnToSort;
            }
        }

        /// <summary>
        /// Gets or sets the order of sorting to apply (for example, 'Ascending' or 'Descending').
        /// </summary>
        public SortOrder Order
        {
            set
            {
                OrderOfSort = value;
            }
            get
            {
                return OrderOfSort;
            }
        }
    }
}