GridControl.CustomSummaryExists Event

Enables you to specify which summaries should be calculated and displayed.

Namespace: DevExpress.Xpf.Grid

Assembly: DevExpress.Xpf.Grid.v20.2.dll

NuGet Packages: DevExpress.WindowsDesktop.Wpf.Grid.Core, DevExpress.Wpf.Grid.Core

Declaration

C#

public event CustomSummaryExistEventHandler CustomSummaryExists

VB.NET

Public Event CustomSummaryExists As CustomSummaryExistEventHandler

Event Data

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

Property	Description
Exists	Gets or sets whether the summary value should be calculated and displayed.
GroupLevel	Gets the nesting level of the group whose summary value is being calculated.
GroupRowHandle	Gets a value identifying the group row whose summary value is about to be calculated.
IsGroupSummary	Gets whether a group summary value is about to be calculated.
IsTotalSummary	Gets whether a total summary value is about to be calculated.
Item	Gets a summary item whose value is about to be calculated.

Remarks

The event is raised before a particular summary value is calculated, allowing cancellation of the calculation. To cancel summary value calculation, set the event parameter’s CustomSummaryExistEventArgs.Exists parameter to false.

• Total Summary

  In this case, the CustomSummaryExistEventArgs.IsTotalSummary parameter returns true. The processed summary item is returned by the CustomSummaryExistEventArgs.Item property. If required, use the summary item’s properties to identify the column where it is displayed.

• Group Summary

  In this case, the CustomSummaryExistEventArgs.IsGroupSummary parameter returns true. The CustomSummaryExistEventArgs.GroupRowHandle property identifies the group for which the summary value is about to be calculated. The processed group summary item is returned by the CustomSummaryExistEventArgs.Item property.

Note

The CustomSummaryExists event does not work in Server Mode.

Example

This example shows how to calculate group summaries and display them within group rows residing at the top grouping level. A group summary represents a value of the aggregate function calculated over all data rows within a group. Group summary items are stored within the grid's GroupSummary collection.

View Example

Window1.xaml

<Window x:Class="DXGrid_DisplayGroupSummaries.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dxg="http://schemas.devexpress.com/winfx/2008/xaml/grid"
    Title="Window1" Height="300" Width="458">
    <Grid>
        <dxg:GridControl x:Name="grid" AutoGenerateColumns="AddNew"
                         CustomSummaryExists="grid_CustomSummaryExists">
            <dxg:GridControl.View>
                <dxg:TableView AutoWidth="True"/>
            </dxg:GridControl.View>
            <dxg:GridControl.GroupSummary>
                <dxg:GridSummaryItem FieldName="Age" SummaryType="Min"/>
                <dxg:GridSummaryItem FieldName="Age" SummaryType="Max"/>
            </dxg:GridControl.GroupSummary>
        </dxg:GridControl>
    </Grid>
</Window>

Window1.xaml.cs

using System;
using System.Collections.Generic;
using System.Windows;
using System.Windows.Documents;
using DevExpress.Data;
using DevExpress.Xpf.Grid;

namespace DXGrid_DisplayGroupSummaries {
    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
            grid.ItemsSource = new AccountList().GetData();
            grid.GroupBy(grid.Columns["Married"], ColumnSortOrder.Ascending);
        }
        private void CreateGroupSummaries() {
            grid.GroupSummary.Add(new GridSummaryItem() {
                FieldName = "Age",
                SummaryType = SummaryItemType.Min
            });
            grid.GroupSummary.Add(new GridSummaryItem() {
                FieldName = "Age",
                SummaryType = SummaryItemType.Max
            });
        }

        private void grid_CustomSummaryExists(object sender, CustomSummaryExistEventArgs e) {
            e.Exists = e.GroupLevel == 0;
        }
    }

    public class AccountList {
        public List<Account> GetData() {
            return CreateAccounts();
        }
        private List<Account> CreateAccounts() {
            List<Account> list = new List<Account>();
            list.Add(new Account() {
                UserName = "Nick White",
                RegistrationDate = DateTime.Today,
                Married = true,
                Age = 42
            });
            list.Add(new Account() {
                UserName = "Jack Rodman",
                RegistrationDate = new DateTime(2009, 5, 10),
                Married = false,
                Age = 30
            });
            list.Add(new Account() {
                UserName = "Sandra Sherry",
                RegistrationDate = new DateTime(2008, 12, 22),
                Married = false,
                Age = 18
            });
            list.Add(new Account() {
                UserName = "Sabrina Vilk",
                RegistrationDate = DateTime.Today,
                Married = true,
                Age = 24
            });
            list.Add(new Account() {
                UserName = "Mike Pearson",
                RegistrationDate = new DateTime(2008, 10, 18),
                Married = true,
                Age = 37
            });
            return list;
        }
    }
    public class Account {
        public string UserName { get; set; }
        public DateTime RegistrationDate { get; set; }
        public bool Married { get; set; }
        public int Age { get; set; }
    }
}

Window1.xaml.vb

Imports Microsoft.VisualBasic
Imports System
Imports System.Collections.Generic
Imports System.Windows
Imports System.Windows.Documents
Imports DevExpress.Data
Imports DevExpress.Xpf.Grid

Namespace DXGrid_DisplayGroupSummaries
    Partial Public Class Window1
        Inherits Window
        Public Sub New()
            InitializeComponent()
            grid.ItemsSource = New AccountList().GetData()
            grid.GroupBy(grid.Columns("Married"), ColumnSortOrder.Ascending)
        End Sub
        Private Sub CreateGroupSummaries()
            grid.GroupSummary.Add(New GridSummaryItem() With {.FieldName = "Age", .SummaryType = SummaryItemType.Min})
            grid.GroupSummary.Add(New GridSummaryItem() With {.FieldName = "Age", .SummaryType = SummaryItemType.Max})
        End Sub

        Private Sub grid_CustomSummaryExists(ByVal sender As Object, ByVal e As CustomSummaryExistEventArgs)
            e.Exists = e.GroupLevel = 0
        End Sub
    End Class

    Public Class AccountList
        Public Function GetData() As List(Of Account)
            Return CreateAccounts()
        End Function
        Private Function CreateAccounts() As List(Of Account)
            Dim list As New List(Of Account)()
            list.Add(New Account() With {.UserName = "Nick White", .RegistrationDate = DateTime.Today, .Married = True, .Age = 42})
            list.Add(New Account() With {.UserName = "Jack Rodman", .RegistrationDate = New DateTime(2009, 5, 10), .Married = False, .Age = 30})
            list.Add(New Account() With {.UserName = "Sandra Sherry", .RegistrationDate = New DateTime(2008, 12, 22), .Married = False, .Age = 18})
            list.Add(New Account() With {.UserName = "Sabrina Vilk", .RegistrationDate = DateTime.Today, .Married = True, .Age = 24})
            list.Add(New Account() With {.UserName = "Mike Pearson", .RegistrationDate = New DateTime(2008, 10, 18), .Married = True, .Age = 37})
            Return list
        End Function
    End Class
    Public Class Account
        Private privateUserName As String
        Public Property UserName() As String
            Get
                Return privateUserName
            End Get
            Set(ByVal value As String)
                privateUserName = value
            End Set
        End Property
        Private privateRegistrationDate As DateTime
        Public Property RegistrationDate() As DateTime
            Get
                Return privateRegistrationDate
            End Get
            Set(ByVal value As DateTime)
                privateRegistrationDate = value
            End Set
        End Property
        Private privateMarried As Boolean
        Public Property Married() As Boolean
            Get
                Return privateMarried
            End Get
            Set(ByVal value As Boolean)
                privateMarried = value
            End Set
        End Property
        Private privateAge As Integer
        Public Property Age() As Integer
            Get
                Return privateAge
            End Get
            Set(ByVal value As Integer)
                privateAge = value
            End Set
        End Property
    End Class
End Namespace

Related GitHub Examples

The following code snippet (auto-collected from DevExpress Examples) contains a reference to the CustomSummaryExists 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.

XAML

wpf-data-grid-display-group-summaries/CS/DXGrid_DisplayGroupSummaries/Window1.xaml#L8

<dxg:GridControl x:Name="grid" AutoGenerateColumns="AddNew"
                 CustomSummaryExists="grid_CustomSummaryExists">
    <dxg:GridControl.View>