Problem with custom sorting

[hwsoderlund]

I need to use custom (server-side) sorting in RadGridView, and I am almost there. I have followed the code examples I found here in the forum and come up with something like the code below (highly simplified example). The problem is, that when I set e.Cancel = true in the RadGridView_Sorting event handler, the sorting indicators disappear from the column headers once the data is returned from the server. I have come up with a work-around (commented out in the example) where I manually set the SortingDescriptors property to the correct value _after_ the data is returned, but should I really need to do that? Everything works fine if I avoid setting e.Cancel to true, but then there will be two sorting operations, first the client-side (incorrectly sorted of course) and then when the wcf call returns the data will be correctly sorted. Is this a bug, or do I have to stick with my ugly work-around?

XAML:

<UserControl x:Class="TestApp02.ListUsers02"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             xmlns:telerik="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls"
             xmlns:teleriknav="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Navigation"
             xmlns:gv="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.GridView"
             xmlns:gv2="clr-namespace:Telerik.Windows.Controls.GridView;assembly=Telerik.Windows.Controls.GridView"
             xmlns:data="clr-namespace:Telerik.Windows.Controls;assembly=Telerik.Windows.Controls.Data">
    <Grid x:Name="LayoutRoot"
          Background="White">

        <gv:RadGridView x:Name="RadGridView1"
                        IsFilteringAllowed="False"
                        MultipleSelect="True"
                        RowIndicatorVisibility="Collapsed"
                        ShowGroupPanel="False"
                        AutoGenerateColumns="False">
            <gv:RadGridView.Columns>

                <gv:GridViewSelectColumn Width="50"></gv:GridViewSelectColumn>

                <gv:GridViewDataColumn Header="ID"
                                       IsCustomSortingEnabled="True"
                                       IsReadOnly="True"
                                       DataMemberBinding="{Binding ID}">
                </gv:GridViewDataColumn>

                <gv:GridViewDataColumn Header="Age"
                                       IsCustomSortingEnabled="True"
                                       IsReadOnly="True"
                                       DataMemberBinding="{Binding Age}">
                </gv:GridViewDataColumn>

                <gv:GridViewDataColumn Header="Name"
                                       IsCustomSortingEnabled="True"
                                       IsReadOnly="True"
                                       DataMemberBinding="{Binding Name}">
                </gv:GridViewDataColumn>

            </gv:RadGridView.Columns>


        </gv:RadGridView>
    </Grid>
</UserControl>

C#:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Telerik.Windows.Controls;
using Telerik.Windows.Data;
using System.ComponentModel;
using System.Windows.Threading;

namespace TestApp02
{
    public partial class ListUsers02 : UserControl
    {
        public ListUsers02()
        {
            InitializeComponent();

            Dispatcher.BeginInvoke(Initialized);
        }

        private void Initialized()
        {
            RadGridView1.Sorting += RadGridView1_Sorting;

            LoadPeople("Name", true);
        }

        void RadGridView1_Sorting(object sender, GridViewSortingEventArgs e)
        {
            if (e.OldSortingState == SortingState.None)
            {
                e.NewSortingState = SortingState.Ascending;
                LoadPeople(e.SortPropertyName, true);
            }
            else if (e.OldSortingState == SortingState.Ascending)
            {
                e.NewSortingState = SortingState.Descending;
                LoadPeople(e.SortPropertyName, false);
            }
            else
            {
                e.NewSortingState = SortingState.None;
                LoadPeople(e.SortPropertyName, true);
            }

            //If I remove this everything is ok, but then the data will be sorted twice
            e.Cancel = true;
        }

        private void LoadPeople(string sortPropertyName, bool ascending)
        {
            //Using a timer to simulate async wcf call
            var timer = new DispatcherTimer();
            timer.Tick += (s, e2) =>
            {
                timer.Stop();

                var people = Person.GetSome();

                if (ascending)
                {
                    if (sortPropertyName == "Name")
                    {
                        RadGridView1.ItemsSource = people.OrderBy(person => person.Name).ToList();
                    }
                    else if (sortPropertyName == "Age")
                    {
                        RadGridView1.ItemsSource = people.OrderBy(person => person.Age).ToList();
                    }
                    else if (sortPropertyName == "ID")
                    {
                        RadGridView1.ItemsSource = people.OrderBy(person => person.ID).ToList();
                    }
                }
                else
                {
                    if (sortPropertyName == "Name")
                    {
                        RadGridView1.ItemsSource = people.OrderByDescending(person => person.Name).ToList();
                    }
                    else if (sortPropertyName == "Age")
                    {
                        RadGridView1.ItemsSource = people.OrderByDescending(person => person.Age).ToList();
                    }
                    else if (sortPropertyName == "ID")
                    {
                        RadGridView1.ItemsSource = people.OrderByDescending(person => person.ID).ToList();
                    }
                }

                //If I enable this, it works, but I think I shouldn't have to
                //SetSortDescriptors(sortPropertyName, ascending);

            };

            //Simulating 0.5 second server call
            timer.Interval = new TimeSpan(0, 0, 0, 0, 500);
            timer.Start();
        }

        private void SetSortDescriptors(string sortPropertyName, bool ascending)
        {
            RadGridView1.SortDescriptors.Clear();

            var sort = new SortDescriptor();
            sort.Member = sortPropertyName;

            if (ascending)
                sort.SortDirection = ListSortDirection.Ascending;
            else
                sort.SortDirection = ListSortDirection.Descending;

            RadGridView1.SortDescriptors.Add(sort);
        }
    }



    public class Person
    {
        public int ID { get; set; }
        public int Age { get; set; }
        public string Name { get; set; }

        public Person(int id, int age, string name)
        {
            this.ID = id;
            this.Age = age;
            this.Name = name;
        }

        public static List<Person> GetSome()
        {
            List<Person> people = new List<Person>();
            people.Add(new Person(1, 45, "Ian"));
            people.Add(new Person(2, 17, "Betty"));
            people.Add(new Person(3, 34, "Marie"));
            people.Add(new Person(4, 65, "Carl"));
            people.Add(new Person(5, 56, "Anna"));
            people.Add(new Person(6, 35, "Jimmy"));

            return people;
        }
    }


}

/Henrik

[Vlad]

Hi Henrik,

You can use only SortingState property of the columns. Please check this demo for more info:
http://demos.telerik.com/silverlight/beta/#GridView/Performance/ServerSide

Best wishes,
Vlad
the Telerik team

Instantly find answers to your questions on the new Telerik Support Portal.
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[hwsoderlund]

Sweet. That simplified things a bit. I'm pasting the updated code below for anybody interested in a concise example of custom sorting.

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using Telerik.Windows.Controls;
using Telerik.Windows.Data;
using System.ComponentModel;
using System.Windows.Threading;
using System.Collections.ObjectModel;

namespace TestApp02
{
    public partial class ListUsers02 : UserControl
    {
        public ListUsers02()
        {
            InitializeComponent();

            Dispatcher.BeginInvoke(Initialized);
        }

        private void Initialized()
        {
            RadGridView1.Sorting += RadGridView1_Sorting;

            LoadPeople("Name", SortingState.Ascending);
        }

        void RadGridView1_Sorting(object sender, GridViewSortingEventArgs e)
        {
            if (e.OldSortingState == SortingState.None)
                e.NewSortingState = SortingState.Ascending;
            else if (e.OldSortingState == SortingState.Ascending)
                e.NewSortingState = SortingState.Descending;
            else
                e.NewSortingState = SortingState.None;

            LoadPeople(e.SortPropertyName, e.NewSortingState);

            e.Cancel = true;
        }

        private void LoadPeople(string sortPropertyName, SortingState sortingState)
        {
            //Using a timer to simulate async wcf call
            var timer = new DispatcherTimer();
            timer.Tick += (s, e2) =>
            {
                timer.Stop();

                var people = Person.GetSome();

                if (sortingState == SortingState.Descending)
                {
                    if (sortPropertyName == "Name")
                    {
                        RadGridView1.ItemsSource = people.OrderByDescending(person => person.Name).ToList();
                    }
                    else if (sortPropertyName == "Age")
                    {
                        RadGridView1.ItemsSource = people.OrderByDescending(person => person.Age).ToList();
                    }
                    else if (sortPropertyName == "ID")
                    {
                        RadGridView1.ItemsSource = people.OrderByDescending(person => person.ID).ToList();
                    }
                }
                else
                {
                    if (sortPropertyName == "Name")
                    {
                        RadGridView1.ItemsSource = people.OrderBy(person => person.Name).ToList();
                    }
                    else if (sortPropertyName == "Age")
                    {
                        RadGridView1.ItemsSource = people.OrderBy(person => person.Age).ToList();
                    }
                    else if (sortPropertyName == "ID")
                    {
                        RadGridView1.ItemsSource = people.OrderBy(person => person.ID).ToList();
                    }
                }

                RadGridView1.Columns[sortPropertyName].SortingState = sortingState;

            };

            //Simulating 0.5 second server call
            timer.Interval = new TimeSpan(0, 0, 0, 0, 500);
            timer.Start();
        }
    }



    public class Person
    {
        public int ID { get; set; }
        public int Age { get; set; }
        public string Name { get; set; }

        public Person(int id, int age, string name)
        {
            this.ID = id;
            this.Age = age;
            this.Name = name;
        }

        public static List<Person> GetSome()
        {
            List<Person> people = new List<Person>();
            people.Add(new Person(1, 45, "Ian"));
            people.Add(new Person(2, 17, "Betty"));
            people.Add(new Person(3, 34, "Marie"));
            people.Add(new Person(4, 65, "Carl"));
            people.Add(new Person(5, 56, "Anna"));
            people.Add(new Person(6, 35, "Jimmy"));

            return people;
        }
    }


}