GridControl.CustomColumnGroup Event

Allows you to create custom rules to group data.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v19.2.dll

Declaration

C#

public event CustomColumnSortEventHandler CustomColumnGroup

VB.NET

Public Event CustomColumnGroup As CustomColumnSortEventHandler

Event Data

The CustomColumnGroup event's data class is CustomColumnSortEventArgs. The following properties provide information specific to this event:

Property	Description
Column	Gets the column whose values are being compared.
Handled	Gets or sets whether a comparison operation is handled and no default processing is required.
ListSourceRowIndex1	Gets the index of the first of the two rows being compared in the data source.
ListSourceRowIndex2	Gets the index of the second of the two rows being compared in the data source.
Result	Gets or sets the result of a custom comparison.
SortOrder	Gets the sort order applied to the column.
Source	Gets the grid control that raised the event.
Value1	Gets the first value being compared.
Value2	Gets the second value being compared.

Remarks

To create custom rules instead of the built-in grouping modes:

1. Set the ColumnBase.SortMode property to Custom.
2. Handle the CustomColumnGroup event.

To change the text displayed in group rows, handle the GridControl.CustomGroupDisplayText event.

Note

The CustomColumnGroup event does not work in Server Mode.

Example

This example creates custom rules to group data. When you group data against the Unit Price column, this rule combines: rows that have values between 0 and 10 into a single group, rows that have values between 10 and 20 into another group, etc.

Note

A complete sample project is available at https://github.com/DevExpress-Examples/how-to-implement-custom-grouping-e1530.

Window1.xaml

<Window x:Class="DXGrid_CustomGrouping.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:dxe="http://schemas.devexpress.com/winfx/2008/xaml/editors"
        xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
        Title="Window1" Height="300" Width="509">
    <Grid>
        <dxg:GridControl x:Name="grid" 
                         CustomColumnGroup="grid_CustomColumnGroup" 
                         CustomGroupDisplayText="grid_CustomGroupDisplayText"
                         ItemsSource="{Binding ListPerson}"
                         >
            <dxg:GridControl.Columns>
                <dxg:GridColumn FieldName="FirstName" />
                <dxg:GridColumn FieldName="LastName" />
                <dxg:GridColumn FieldName="UnitPrice" SortMode="Custom" GroupIndex="0">
                    <dxg:GridColumn.EditSettings>
                        <dxe:SpinEditSettings DisplayFormat="c2" />
                    </dxg:GridColumn.EditSettings>
                </dxg:GridColumn>
            </dxg:GridControl.Columns>
            <dxg:GridControl.View>
                <dxg:TableView AutoWidth="True" />
            </dxg:GridControl.View>
        </dxg:GridControl>
    </Grid>
</Window>

MyViewModel.cs

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

namespace DXGrid_CustomGrouping {
    public class MyViewModel  {
        public MyViewModel() {
            CreateList();
        }


        public ObservableCollection<Person> ListPerson { get; set; }

        void CreateList() {
            ListPerson = new ObservableCollection<Person>();
            for (int i = 0; i < 100; i++) {
                Person p = new Person(i);
                ListPerson.Add(p);
            }
        }
    }

    public class Person  {
        public Person() {

        }
        public Person(int i) {
            FirstName = "FirstName" + i;
            LastName = "LastName" + i;
          UnitPrice = i ;

        }

        string _firstName;

        public string FirstName {
            get { return _firstName; }
            set {
                _firstName = value;

            }
        }
        public string LastName { get; set; }
        int _age;

        public int UnitPrice {
            get { return _age; }
            set { _age = value; }
        }



    }
}

MyViewModel.vb

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

Namespace DXGrid_CustomGrouping
    Public Class MyViewModel
        Public Sub New()
            CreateList()
        End Sub


        Public Property ListPerson() As ObservableCollection(Of Person)

        Private Sub CreateList()
            ListPerson = New ObservableCollection(Of Person)()
            For i As Integer = 0 To 99
                Dim p As New Person(i)
                ListPerson.Add(p)
            Next i
        End Sub
    End Class

    Public Class Person
        Public Sub New()

        End Sub
        Public Sub New(ByVal i As Integer)
            FirstName = "FirstName" & i
            LastName = "LastName" & i
          UnitPrice = i

        End Sub

        Private _firstName As String

        Public Property FirstName() As String
            Get
                Return _firstName
            End Get
            Set(ByVal value As String)
                _firstName = value

            End Set
        End Property
        Public Property LastName() As String
        Private _age As Integer

        Public Property UnitPrice() As Integer
            Get
                Return _age
            End Get
            Set(ByVal value As Integer)
                _age = value
            End Set
        End Property



    End Class
End Namespace

Window1.xaml.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;
using System.Collections;
using DevExpress.Xpf.Grid;

namespace DXGrid_CustomGrouping {
    /// <summary>
    /// Interaction logic for Window1.xaml
    /// </summary>
    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
            this.DataContext = new MyViewModel();

        }

        private void grid_CustomColumnGroup(object sender,
                                            CustomColumnSortEventArgs e) {
            if (e.Column.FieldName == "UnitPrice") {
                double x = Math.Floor(Convert.ToDouble(e.Value1) / 10);
                double y = Math.Floor(Convert.ToDouble(e.Value2) / 10);
                int res = Comparer.Default.Compare(x, y);
                if (x > 9 && y > 9) res = 0;
                e.Result = res;
                e.Handled = true;
            }
        }
        private void grid_CustomGroupDisplayText(object sender,
                                                 CustomGroupDisplayTextEventArgs e) {
            if (e.Column.FieldName != "UnitPrice") return;
            int groupLevel = grid.GetRowLevelByRowHandle(e.RowHandle);
            if (groupLevel != e.Column.GroupIndex) return;
            string interval = IntervalByValue(e.Value);
            e.DisplayText = interval;
        }
        // Gets the text that represents the interval which contains the specified value.
        private string IntervalByValue(object val) {
            double d = Math.Floor(Convert.ToDouble(val) / 10);
            string ret = string.Format("{0:c} - {1:c} ", d * 10, (d + 1) * 10);
            if (d > 9) ret = string.Format(">= {0:c} ", 100);
            return ret;
        }

    }
}

Window1.xaml.vb

Imports System
Imports System.Collections.Generic
Imports System.Linq
Imports System.Text
Imports System.Windows
Imports System.Windows.Controls
Imports System.Windows.Data
Imports System.Windows.Documents
Imports System.Windows.Input
Imports System.Windows.Media
Imports System.Windows.Media.Imaging
Imports System.Windows.Navigation
Imports System.Windows.Shapes
Imports System.Collections
Imports DevExpress.Xpf.Grid

Namespace DXGrid_CustomGrouping
    ''' <summary>
    ''' Interaction logic for Window1.xaml
    ''' </summary>
    Partial Public Class Window1
        Inherits Window

        Public Sub New()
            InitializeComponent()
            Me.DataContext = New MyViewModel()

        End Sub

        Private Sub grid_CustomColumnGroup(ByVal sender As Object, ByVal e As CustomColumnSortEventArgs)
            If e.Column.FieldName = "UnitPrice" Then
                Dim x As Double = Math.Floor(Convert.ToDouble(e.Value1) / 10)
                Dim y As Double = Math.Floor(Convert.ToDouble(e.Value2) / 10)
                Dim res As Integer = Comparer.Default.Compare(x, y)
                If x > 9 AndAlso y > 9 Then
                    res = 0
                End If
                e.Result = res
                e.Handled = True
            End If
        End Sub
        Private Sub grid_CustomGroupDisplayText(ByVal sender As Object, ByVal e As CustomGroupDisplayTextEventArgs)
            If e.Column.FieldName <> "UnitPrice" Then
                Return
            End If
            Dim groupLevel As Integer = grid.GetRowLevelByRowHandle(e.RowHandle)
            If groupLevel <> e.Column.GroupIndex Then
                Return
            End If
            Dim interval As String = IntervalByValue(e.Value)
            e.DisplayText = interval
        End Sub
        ' Gets the text that represents the interval which contains the specified value.
        Private Function IntervalByValue(ByVal val As Object) As String
            Dim d As Double = Math.Floor(Convert.ToDouble(val) / 10)
            Dim ret As String = String.Format("{0:c} - {1:c} ", d * 10, (d + 1) * 10)
            If d > 9 Then
                ret = String.Format(">= {0:c} ", 100)
            End If
            Return ret
        End Function

    End Class
End Namespace

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the CustomColumnGroup event.

Note

The algorithm used to collect these code examples remains a work in progress. Accordingly, the links and snippets below may produce inaccurate results. If you encounter an issue with code examples below, please use the feedback form on this page to report the issue.

C#

how-to-implement-custom-grouping-e1530/CS/DXGrid_CustomGrouping/Window1.xaml#L9

<dxg:GridControl x:Name="grid"
                 CustomColumnGroup="grid_CustomColumnGroup"
                 CustomGroupDisplayText="grid_CustomGroupDisplayText"