[Solved] Problems with custom sorting

[Dario]

I ran into some problems while trying to implement a custom sorting option on my custom column class. I've extended the GridViewDataColumn class and in order to make my column sortable I have overridden "CanSort()" method to always return true.

The point is, I only want to use the UI functionality of the grid, but then I want  to intercept the "Sorting" event, do my custom sorting server side, and cancel the grid's "sorting" implementation.

This is all well until  I get get the exception saying my data must implement IComparable, and that is a problem for me, because I use some dynamic data as a grid's source and cannot implement IComparable. Also, because I only want to catch sorting event, and not use the logic behind it, I hope I can somehow overcome this problem. Can I?

[Rossen Hristov]

Hello Dario ,

Since you cannot implement IComparable, you will need to cancel the sorting like this:

using System.Windows.Controls;
using Telerik.Windows.Controls;

namespace TicketID_235633_CustomSortingProblems
{
    public partial class MainPage : UserControl
    {
        public MainPage()
        {
            this.InitializeComponent();

            var cc = new CustomColumn();
            this.playersGrid.Columns.Add(cc);
            this.playersGrid.Sorting += OnSorting;
            this.playersGrid.ItemsSource = Club.GetPlayers();
        }

        private static SortingState GetNextSortingState(SortingState currentState)
        {
            switch (currentState)
            {
                case SortingState.None:
                    return SortingState.Ascending;
                case SortingState.Ascending:
                    return SortingState.Descending;
                case SortingState.Descending:
                    return SortingState.None;
                default:
                    return SortingState.None;
            }
        }

        private static void OnSorting(object sender, GridViewSortingEventArgs e)
        {
            if (e.Column.GetType() == typeof (CustomColumn))
            {
                e.Cancel = true;
                e.SortingState = GetNextSortingState(e.SortingState);
            }
        }
    }
}

Best wishes,
Ross
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
Check out the tips for optimizing your support resource searches.

[Dario]

Tnx Ross, it works now :)