GridControl.CustomColumnGroup Event

Allows you to create custom rules to group data.

Namespace: DevExpress.Xpf.Grid

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

Declaration

public event CustomColumnSortEventHandler CustomColumnGroup
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.

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