GridControl.CustomGroupDisplayText Event

Enables you to provide custom content for group rows.

Namespace: DevExpress.Xpf.Grid

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

Declaration

C#

public event CustomGroupDisplayTextEventHandler CustomGroupDisplayText

VB.NET

Public Event CustomGroupDisplayText As CustomGroupDisplayTextEventHandler

Event Data

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

Property	Description
Cell	Gets or sets the CellValue object consisting of information about the cell being processed. Inherited from CellValueEventArgs.
Column	Gets a column that contains the edited cell. Inherited from CellValueEventArgs.
DisplayText	Gets or sets the text displayed within the processed group row.
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Row	Gets the processed row. Inherited from RowEventArgs.
RowHandle	Gets the processed row’s handle. Inherited from RowEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.
Value	Gets or sets the processed cell’s value. Inherited from CellValueEventArgs.

The event data class exposes the following methods:

Method	Description
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

You can group rows using custom rules by handling the GridControl.CustomColumnGroup event. In this instance, it may be useful to replace the default text displayed within group rows. To do this, handle the CustomGroupDisplayText event. The event arguments allow you to easily identify group rows and replace their display text.

In the CustomGroupDisplayText event handler, you can use methods listed in the Obtain and Set Cell Values in Code topic to obtain the required column values and the DisplayText property to a string value you want to display.

The code sample below shows how to display a particular column’s value in the group row:

C#

private void grid_CustomGroupDisplayText(object sender, CustomGroupDisplayTextEventArgs e) {
    e.DisplayText = grid.GetCellDisplayText(e.RowHandle, "Id");
} 

VB.NET

Private Sub grid_CustomGroupDisplayText(ByVal sender As Object, ByVal e As CustomGroupDisplayTextEventArgs)
    e.DisplayText = grid.GetCellDisplayText(e.RowHandle, "Id")
End Sub 

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 snippets (auto-collected from DevExpress Examples) contain references to the CustomGroupDisplayText 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-display-custom-text-within-data-cells-and-groups-t327301/CS/DXSample/MainWindow.xaml#L15

CustomColumnDisplayText="GridControl_CustomColumnDisplayText"
CustomGroupDisplayText="GridControl_CustomGroupDisplayText">
<dxg:GridControl.Columns>

how-to-implement-custom-grouping-e1530/CS/DXGrid_CustomGrouping/Window1.xaml#L10

CustomColumnGroup="grid_CustomColumnGroup"
CustomGroupDisplayText="grid_CustomGroupDisplayText"
ItemsSource="{Binding ListPerson}"