GridControl.CustomGroupDisplayText Event

Enables you to provide custom content for group rows.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v20.1.dll

Declaration

public event CustomGroupDisplayTextEventHandler CustomGroupDisplayText
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.

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:

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

Examples

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.

<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>
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; }
        }
    }
}
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;
        }

    }
}
See Also