GridControl.CustomColumnGroup Event
Allows you to create custom rules to group data.
Namespace: DevExpress.Xpf.Grid
Assembly: DevExpress.Xpf.Grid.v20.1.dll
NuGet Packages: DevExpress.WindowsDesktop.Wpf.Grid.Core, DevExpress.Wpf.Grid.Core
Declaration
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:
- Set the ColumnBase.SortMode property to Custom.
- 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.
<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;
}
}
}
Related GitHub Examples
The following code snippet (auto-collected from DevExpress Examples) contains a reference to the CustomColumnGroup event.
Note
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