Question

Im building a datatable with 2 columns with listview and i need to order the datatable by the second column.

It look something like this:

Name – Points

——————

John      –  10
Peter     –  14
Marcus  –  9

So how do I order it by points?



SOLVED!!

        private class PointsComparer : IComparer
        {
            private const int pointsColumnIndex = 1;

            public int Compare(object x, object y)
            {
                ListViewItem listX = (ListViewItem)x;
                ListViewItem listY = (ListViewItem)y;

                // Convert column text to numbers before comparing.
                // If the conversion fails, just use the value 0.
                decimal listXVal, listYVal;
                try
                {
                    listXVal = Decimal.Parse(listX.SubItems[pointsColumnIndex].Text);
                }
                catch
                {
                    listXVal = 0;
                }

                try
                {
                    listYVal = Decimal.Parse(listY.SubItems[pointsColumnIndex].Text);
                }
                catch
                {
                    listYVal = 0;
                }

                return (-Decimal.Compare(listXVal, listYVal));
            }
        }

This worked as a charm for me.

Answer 1

Use ListViewItemSorter property to set custom IComparer for your items. Then simply call Sort() method:

// adding data
listView1.Items.Add(new ListViewItem(new string[] { "John", "10" }));
listView1.Items.Add(new ListViewItem(new string[] { "Peter", "14" }));
listView1.Items.Add(new ListViewItem(new string[] { "Markus", "9" }));
// setting comparer and sorting
listView1.ListViewItemSorter = new PointsComparer();
listView1.Sort();

Here is sample of comparer which you can use to compare points:

private class PointsComparer : IComparer
{
    private const int pointsColumnIndex = 1;

    public int Compare(object x, object y)
    {
        int pointsX = Int32.Parse(((ListViewItem)x).SubItems[pointsColumnIndex].Text);
        int pointsY = Int32.Parse(((ListViewItem)y).SubItems[pointsColumnIndex].Text);
        return pointsX.CompareTo(pointsY);
    }
}

Or, as I posted previously, you can use comparer by column text from msdn sample.

UPDATE: You can pass desired sort order to instance of your comparer:

private class PointsComparer : IComparer
{
    private const int pointsColumnIndex = 1;
    private SortOrder _sortOrder;            

    public PointsComparer(SortOrder sortOrder)
    {
        _sortOrder = sortOrder;
    }

    public int Compare(object x, object y)
    {
        int pointsX = Int32.Parse(((ListViewItem)x).SubItems[pointsColumnIndex].Text);
        int pointsY = Int32.Parse(((ListViewItem)y).SubItems[pointsColumnIndex].Text);
        int comparisonResult = pointsX.CompareTo(pointsY);

        switch (_sortOrder)
        {
            case SortOrder.Ascending:
                return comparisonResult;
            case SortOrder.Descending:
                return (-1) * comparisonResult;
            default:
                return 0;
        }
    }
}

Then use it like this:

listView1.ListViewItemSorter = new PointsComparer(SortOrder.Descending);