code/Controls/ListViewColumnSorter.cs

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using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace Sylloge.Controls
{
    #region Sorting Class

    public class ListViewColumnSorter : System.Collections.IComparer
    {
        /* NOTE: How to use this class:
         
            public class MyClass
            {
                ListViewColumnSorter TempColumnSorter = new ListViewColumnSorter();
                ListView TempListView = new ListView();

                public MyClass() {
                    TempListView.ListViewItemSorter = TempColumnSorter;
                    TempListView.ColumnClick += new System.Windows.Forms.ColumnClickEventHandler(TempListView_ColumnClick);
                }

                private void TempListView_ColumnClick(object sender, System.Windows.Forms.ColumnClickEventArgs e)
                {
                    if (e.Column == this.FieldColumnSort.SortColumn) {
                        // Reverse the current sort direction for this column.
                        if (TempColumnSorter.Order == SortOrder.Ascending) {
                            TempColumnSorter.Order = SortOrder.Descending;
                        } else {
                            TempColumnSorter.Order = SortOrder.Ascending;
                        }
                    } else {
                        // Set the column number that is to be sorted; default to ascending.
                        TempColumnSorter.SortColumn = e.Column;
                        TempColumnSorter.Order = SortOrder.Ascending;
                    }
                    // Perform the sort with these new sort options.
                    TempListView.Sort();
                }
            }
        */

        private int m_ColumnToSort;
        private SortOrder m_OrderOfSort;
        private CaseInsensitiveComparer m_ObjectCompare;

        public ListViewColumnSorter()
        {
            // Initialize the column to '0'
            this.m_ColumnToSort = 0;
            // Initialize the sort order to 'none'
            this.m_OrderOfSort = SortOrder.None;
            // Initialize the CaseInsensitiveComparer object
            this.m_ObjectCompare = new CaseInsensitiveComparer();
        }

        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 = this.m_ObjectCompare.Compare(listviewX.SubItems[this.m_ColumnToSort].Text, listviewY.SubItems[this.m_ColumnToSort].Text);
            // Calculate correct return value based on object comparison
            if (this.m_OrderOfSort == SortOrder.Ascending) {
                // Ascending sort is selected, return normal result of compare operation
                return compareResult;
            } else if (this.m_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;
            }
        }

        public int SortColumn
        {
            set { this.m_ColumnToSort = value; }
            get { return this.m_ColumnToSort; }
        }

        public SortOrder Order
        {
            set { this.m_OrderOfSort = value; }
            get { return this.m_OrderOfSort; }
        }
    }

    #endregion
}