C# ListViewColumnSorter with NEW and AUTO key

Guide.cs

// 1. Paste the following code into the class for the form:

private ListViewColumnSorter lvwColumnSorter = new ListViewColumnSorter();

// 2. Paste the following code into the constructor for the form, after the call to the InitializeComponent method:

this.listView1.ListViewItemSorter = lvwColumnSorter;

// 3. Paste the following code into the ColumnClick event for the ListView control:

// 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();

ListViewColumnSorter.cs

using System.Collections;
using System.Windows.Forms;

/// <summary>
/// This class is an implementation of the 'IComparer' interface.
/// </summary>
public class ListViewColumnSorter : IComparer
{
    /// <summary>
    /// Specifies the column to be sorted
    /// </summary>
    private int ColumnToSort;
    /// <summary>
    /// Specifies the order in which to sort (i.e. 'Ascending').
    /// </summary>
    private SortOrder OrderOfSort;
    /// <summary>
    /// Case insensitive comparer object
    /// </summary>
    private CaseInsensitiveComparer ObjectCompare;

    /// <summary>
    /// Class constructor.  Initializes various elements
    /// </summary>
    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;

        // Deal with NEWKEY and AUTOKEY
        if (listviewX.SubItems[0].Text == "*NEW" || listviewY.SubItems[0].Text == "*NEW") return -1;
        if (listviewX.SubItems[0].Text == "[AUTO]") return (listviewY.SubItems[0].Text == "*NEW" ? 1 : -1);
        if (listviewY.SubItems[0].Text == "[AUTO]") return (listviewX.SubItems[0].Text == "*NEW" ? 1 : -1);

        // 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;
        }
    }
}