GridControlBase.CustomGroupDisplayText Event

Enables you to provide custom content for group rows.

Namespace: DevExpress.UI.Xaml.Grid

Assembly: DevExpress.UI.Xaml.Grid.v21.2.dll

NuGet Package: DevExpress.Uwp.Controls

Declaration

C#

public event CustomGroupDisplayTextEventHandler CustomGroupDisplayText

VB.NET

Public Event CustomGroupDisplayText As CustomGroupDisplayTextEventHandler

Event Data

The CustomGroupDisplayText event's data class is DevExpress.UI.Xaml.Grid.CustomGroupDisplayTextEventArgs.

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.

Example

This example shows how to group rows using custom rules. When grouping by the 'Unit Price' column, the rows in this column that have values between 0 and 10 should be combined into a single group. Rows whose values fall between 10 and 20 should be combined into another group, etc.

XAML

<Page
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="using:HowToCustomGrouping"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:Grid="using:DevExpress.UI.Xaml.Grid"
    x:Class="HowToCustomGrouping.MainPage"
    mc:Ignorable="d">
    <Grid>
        <Grid:GridControl Name="grid" CustomColumnGroup="GridControl_CustomColumnGroup" CustomGroupDisplayText="GridControl_CustomGroupDisplayText" Background="Black" Foreground="White" >
            <Grid:GridControl.Columns>
                <Grid:GridTextColumn FieldName="ProductName" />
                <Grid:GridTextColumn FieldName="Supplier" />
                <Grid:GridTextColumn FieldName="UnitPrice" SortMode="Custom"/>
                <Grid:GridTextColumn FieldName="Quantity" />
            </Grid:GridControl.Columns>
        </Grid:GridControl>
    </Grid>
</Page>

C#

using System;
using System.Collections.Generic;
using Windows.UI.Xaml.Controls;

namespace HowToCustomGrouping
{
    public sealed partial class MainPage : Page
    {
        public MainPage()
        {
            this.InitializeComponent();
            grid.ItemsSource = new ProductList();
            grid.Columns["UnitPrice"].GroupIndex = 0;
        }

        private void GridControl_CustomColumnGroup(object sender, DevExpress.UI.Xaml.Grid.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<double>.Default.Compare(x,y);
                if (x > 9 && y > 9) res = 0;
                e.Result = res;
                e.Handled = true;
            }
        }

        private void GridControl_CustomGroupDisplayText(object sender, DevExpress.UI.Xaml.Grid.CustomGroupDisplayTextEventArgs e) {
            if (e.Column.FieldName != "UnitPrice") return;
            string interval = IntervalByValue(e.Value);
            e.DisplayText = interval;

        }
        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;
        }

    }
}

VB.NET

Imports HowToCustomGrouping.Data

Public NotInheritable Class MainPage
    Inherits Page
    Public Sub New()
        InitializeComponent()
        grid.ItemsSource = New ProductList()
        grid.Columns("UnitPrice").GroupIndex = 0
    End Sub
    Private Sub GridControl_CustomColumnGroup(sender As Object, e As DevExpress.UI.Xaml.Grid.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(Of Double).[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 GridControl_CustomGroupDisplayText(sender As Object, e As DevExpress.UI.Xaml.Grid.CustomGroupDisplayTextEventArgs)
        If e.Column.FieldName <> "UnitPrice" Then
            Return
        End If
        Dim interval As String = IntervalByValue(e.Value)
        e.DisplayText = interval

    End Sub
    Private Function IntervalByValue(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