Sorting Modes and Custom Sorting

• May 05, 2018
• 5 minutes to read

Note

Sorting by display text and custom sorting are not supported in Server Mode.

Overview

The DXGrid supports data sorting by cell values and display text. For each column, you can specify how their data should be sorted - by the edit or display values, or using custom logic. To specify the required sort mode, use the ColumnBase.SortMode property.

• Sorting by Edit Values (Default)

  Sorts a column’s data by its edit values. To enable this mode, set the ColumnBase.SortMode property to ColumnSortMode.Value.

• Sorting by Display Text

  Sorts a column’s data by its display text (the strings displayed within data cells). To enable this mode, set the ColumnBase.SortMode property to ColumnSortMode.DisplayText.

• Custom Sorting

  Enables you to implement custom sorting rules. To do this, handle the GridControl.CustomColumnSort event. To enable this mode, set the ColumnBase.SortMode property to ColumnSortMode.Custom.

Custom sorting

To sort column values using custom logic, set a column’s ColumnBase.SortMode property to ColumnSortMode.Custom, and handle the GridControl.CustomColumnSort event.

When this event is fired, two rows should be compared. The column being processed is specified by the Column parameter. The Value1 and Value2 parameters identify the values of the rows within this column. The result of the custom comparison should be set to the Result parameter as follows:

• -1 if the first row should be positioned above the second row when data is sorted in ascending order. When data is sorted in descending order, the first row will be positioned below the second row.
• 1 if the first row should be positioned below the second row when data is sorted in ascending order. When data is sorted in descending order the first row will be positioned above the second row.
• 0 to indicate that the rows are equal. In this case, the rows will be arranged within a View according to their indices in a data source.

The event parameter’s Handled property should be set to true if the comparison operation was handled. You can leave this parameter set to false, to invoke the default comparison mechanism after your event handler has finished. In this instance, the custom comparison operation’s result is ignored.

Sorting by another column

GridControl’s default sorting and grouping behavior is as follows. On clicking a column header or changing the ColumnBase.SortOrder property, data is sorted by the corresponding field. On grouping against a column, data groups are created based on the values of this column.

The ColumnBase.SortFieldName property allows you to change this behavior. When sorting/grouping is applied to a specific column, you can sort/group data against another field instead. To do this, set the ColumnBase.SortFieldName property to the required field name.

Example: How to Implement Custom Sorting

This example demonstrates how to implement custom sorting in the Grid Control. To do this, handle the GridControl.CustomColumnSort event, assign your custom sorted list to the e.Result property and set the e.Handled property to True.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-implement-custom-sorting-e963.

SchedulerSource.cs

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace CustomSorting {
    public class SchedulerData {
        const int daysInWeek = 7;
        string[] employees = new string[] { "Jane", "Martin", "John", "Jack", "Amanda", "Carmen", "Wins", "Todd", "Ashley" };
        Random rnd = new Random();
        public List<SchedulerItem> Items { get; set; }
        public SchedulerData() {
            Items = new List<SchedulerItem>();
            GenerateRandomData();
        }
        void GenerateRandomData() {
            for (int i = 0; i < daysInWeek; i++) {
                int e1 = rnd.Next(employees.Length - 1);
                int e2 = e1 + 1;
                string day = DateTime.Today.AddDays(i).DayOfWeek.ToString();
                Items.Add(new SchedulerItem() { Day = day, Employee = employees[e1] });
                Items.Add(new SchedulerItem() { Day = day, Employee = employees[e2] });
            }
        }
    }

    public class SchedulerItem {
        public string Day { get; set; }
        public string Employee { get; set; }
    }
}

Window1.xaml.cs

using System.Windows;
using System.Collections.Generic;
using DevExpress.Xpf.Grid;
using CustomSorting;
using System;

namespace CustomSorting {

    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
            DataContext = new SchedulerData();
        }

        void OnCustomColumnSort(object sender, CustomColumnSortEventArgs e) {
            if (e.Column.FieldName == "Day") {
                int dayIndex1 = GetDayIndex((string)e.Value1);
                int dayIndex2 = GetDayIndex((string)e.Value2);
                e.Result = dayIndex1.CompareTo(dayIndex2);
                e.Handled = true;
            }
        }

        int GetDayIndex(string day) {
            return (int)Enum.Parse(typeof(DayOfWeek), day);
        }
    }
}

Window1.xaml

<Window x:Class="CustomSorting.Window1" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid" 
        Title="Custom Column Sort" Height="300" Width="300" >
    <Grid>
        <dxg:GridControl ItemsSource="{Binding Items}" Grid.Row="1" CustomColumnSort="OnCustomColumnSort">
            <dxg:GridControl.Columns>
                <dxg:GridColumn FieldName="Day" GroupIndex="0" SortMode="Custom" />
                <dxg:GridColumn FieldName="Employee" />
            </dxg:GridControl.Columns>
            <dxg:GridControl.View>
                <dxg:TableView />
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>

Window1.xaml.vb

Imports System.Windows
Imports System.Collections.Generic
Imports DevExpress.Xpf.Grid
Imports CustomSorting
Imports System

Namespace CustomSorting

    Partial Public Class Window1
        Inherits Window

        Public Sub New()
            InitializeComponent()
            DataContext = New SchedulerData()
        End Sub

        Private Sub OnCustomColumnSort(ByVal sender As Object, ByVal e As CustomColumnSortEventArgs)
            If e.Column.FieldName = "Day" Then
                Dim dayIndex1 As Integer = GetDayIndex(DirectCast(e.Value1, String))
                Dim dayIndex2 As Integer = GetDayIndex(DirectCast(e.Value2, String))
                e.Result = dayIndex1.CompareTo(dayIndex2)
                e.Handled = True
            End If
        End Sub

        Private Function GetDayIndex(ByVal day As String) As Integer
            Return DirectCast(System.Enum.Parse(GetType(DayOfWeek), day), Integer)
        End Function
    End Class
End Namespace

SchedulerSource.vb

Imports System
Imports System.Collections.Generic
Imports System.Collections.ObjectModel
Imports System.Linq
Imports System.Text
Imports System.Threading.Tasks

Namespace CustomSorting
    Public Class SchedulerData
        Private Const daysInWeek As Integer = 7
        Private employees() As String = { "Jane", "Martin", "John", "Jack", "Amanda", "Carmen", "Wins", "Todd", "Ashley" }
        Private rnd As New Random()
        Public Property Items() As List(Of SchedulerItem)
        Public Sub New()
            Items = New List(Of SchedulerItem)()
            GenerateRandomData()
        End Sub
        Private Sub GenerateRandomData()
            For i As Integer = 0 To daysInWeek - 1
                Dim e1 As Integer = rnd.Next(employees.Length - 1)
                Dim e2 As Integer = e1 + 1
                Dim day As String = Date.Today.AddDays(i).DayOfWeek.ToString()
                Items.Add(New SchedulerItem() With {.Day = day, .Employee = employees(e1)})
                Items.Add(New SchedulerItem() With {.Day = day, .Employee = employees(e2)})
            Next i
        End Sub
    End Class

    Public Class SchedulerItem
        Public Property Day() As String
        Public Property Employee() As String
    End Class
End Namespace