How to: Create a Custom Summary to Display the Distinct Value Count

• Aug 01, 2019
• 3 minutes to read

This example demonstrates how to count distinct values (the number of orders with equal product quantities) and display the result in the pivot grid.

This example handles the CustomSummary event that occurs when the control calculates a summary for a field whose SummaryType is PivotSummaryType.Custom. The event handler calls the e.CreateDrillDownDataSource method to retrieve the underlying data rows for the current cell, counts distinct values and returns the result to the e.CustomValue property.

Note

The complete sample project How to Create a Custom Summary Type to Display the Distinct Value Count is available in the DevExpress Examples repository.

MainWindow.xaml

<dx:ThemedWindow x:Class="DXPivotGrid_CustomSummary.MainWindow" mc:Ignorable="d" Title="MainWindow" Height="450" Width="800" 
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core" 
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008" 
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
    xmlns:local="clr-namespace:DXPivotGrid_CustomSummary" 
    xmlns:dxpg="http://schemas.devexpress.com/winfx/2008/xaml/pivotgrid">
    <Grid>

        <dxpg:PivotGridControl CustomSummary="pivotGridControl1_CustomSummary" Loaded="PivotGridControl1_Loaded" Name="pivotGridControl1">
            <dxpg:PivotGridControl.Fields>
                <dxpg:PivotGridField Name="fieldCategoryName" FieldName="CategoryName" Area="RowArea" AreaIndex="0" Caption="Category Name" />
                <dxpg:PivotGridField Name="fieldProductName" FieldName="ProductName" Area="RowArea" AreaIndex="1" Caption="Product Name" />
                <dxpg:PivotGridField Name="fieldOrderDate" FieldName="OrderDate" Area="ColumnArea" AreaIndex="0" Caption="OrderDate" GroupInterval="DateYear" />
                <dxpg:PivotGridField Name="fieldQuantity" FieldName="Quantity" Area="DataArea" AreaIndex="0" Caption="Quantity" />
                <dxpg:PivotGridField Name="fieldQuantityDistinctCount" FieldName="Quantity" Area="DataArea" AreaIndex="1" Caption="Count Distinct" SummaryType="Custom" />
            </dxpg:PivotGridControl.Fields>
        </dxpg:PivotGridControl>

    </Grid>
</dx:ThemedWindow>

MainWindow.xaml.vb

Imports DevExpress.DataAccess.Excel
Imports System
Imports System.Collections
Imports System.Windows

Namespace DXPivotGrid_CustomSummary
  ''' <summary>
  ''' Interaction logic for MainWindow.xaml
  ''' </summary>
  Partial Public Class MainWindow
    Inherits DevExpress.Xpf.Core.ThemedWindow

    Private ds As New ExcelDataSource()
    Public Sub New()
      InitializeComponent()

      ds.Name = "Excel Data Source"
      ds.FileName = "SalesPerson.xlsx"
      Dim worksheetSettings As New ExcelWorksheetSettings("Data")
      ds.SourceOptions = New ExcelSourceOptions(worksheetSettings)
      ds.Fill()

      pivotGridControl1.DataSource = ds
    End Sub

    Private Sub pivotGridControl1_CustomSummary(ByVal sender As Object, ByVal e As DevExpress.Xpf.PivotGrid.PivotCustomSummaryEventArgs)
      Dim name_Renamed As String = e.DataField.FieldName

      Dim list As IList = e.CreateDrillDownDataSource()
      Dim ht As New Hashtable()
      For i As Integer = 0 To list.Count - 1
        Dim row As DevExpress.XtraPivotGrid.PivotDrillDownDataRow = TryCast(list(i), DevExpress.XtraPivotGrid.PivotDrillDownDataRow)
        Dim v As Object = row(name_Renamed)
        If v IsNot Nothing AndAlso v IsNot DBNull.Value Then
          ht(v) = Nothing
        End If
      Next i
      e.CustomValue = ht.Count
    End Sub

    Private Sub PivotGridControl1_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
      pivotGridControl1.BestFit()
    End Sub
  End Class
End Namespace

MainWindow.xaml.cs

using DevExpress.DataAccess.Excel;
using System;
using System.Collections;
using System.Windows;

namespace DXPivotGrid_CustomSummary
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : DevExpress.Xpf.Core.ThemedWindow
    {
        ExcelDataSource ds = new ExcelDataSource();
        public MainWindow()
        {
            InitializeComponent();

            ds.Name = "Excel Data Source";
            ds.FileName = "SalesPerson.xlsx";
            ExcelWorksheetSettings worksheetSettings = new ExcelWorksheetSettings("Data");
            ds.SourceOptions = new ExcelSourceOptions(worksheetSettings);
            ds.Fill();

            pivotGridControl1.DataSource = ds;
        }

        private void pivotGridControl1_CustomSummary(object sender, DevExpress.Xpf.PivotGrid.PivotCustomSummaryEventArgs e)
        {
            string name = e.DataField.FieldName;

            IList list = e.CreateDrillDownDataSource();
            Hashtable ht = new Hashtable();
            for (int i = 0; i < list.Count; i++)
            {
                DevExpress.XtraPivotGrid.PivotDrillDownDataRow row = list[i] as DevExpress.XtraPivotGrid.PivotDrillDownDataRow;
                object v = row[name];
                if (v != null && v != DBNull.Value)
                    ht[v] = null;
            }
            e.CustomValue = ht.Count;
        }

        private void PivotGridControl1_Loaded(object sender, RoutedEventArgs e)
        {
            pivotGridControl1.BestFit();
        }
    }
}