How to: Group Date-Time Values

<Window x:Class="HowToBindToMDB.MainWindow" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
        xmlns:dxpg="http://schemas.devexpress.com/winfx/2008/xaml/pivotgrid" 
        Title="MainWindow" Height="350" Width="525"  Loaded="Window_Loaded">
    <Grid>
        <dxpg:PivotGridControl HorizontalAlignment="Left" Name="pivotGridControl1" 
                               VerticalAlignment="Top">
            <dxpg:PivotGridControl.Fields>
                <dxpg:PivotGridField Name="fieldYear" FieldName="OrderDate" Area="RowArea" 
                                     Caption="Year" GroupInterval="DateYear" />
                <dxpg:PivotGridField Name="fieldQuarter" FieldName="OrderDate" Area="RowArea" 
                                     Caption="Quarter" GroupInterval="DateQuarter" 
                                     ValueFormat="Qtr {0}" />
                <dxpg:PivotGridField Name="fieldMonth" FieldName="OrderDate" Area="RowArea" 
                                     Caption="Month" GroupInterval="DateMonth" />
                <dxpg:PivotGridField Name="fieldExtendedPrice" FieldName="Extended Price" 
                                     Area="DataArea" CellFormat="c0" />
            </dxpg:PivotGridControl.Fields>
        </dxpg:PivotGridControl>
    </Grid>
</Window>

using System.Data;
using System.Data.OleDb;
using System.Windows;
using DevExpress.Xpf.PivotGrid;
using HowToBindToMDB.NwindDataSetTableAdapters;

namespace HowToBindToMDB {
    /// <summary> 
    /// Interaction logic for MainWindow.xaml 
    /// </summary> 
    public partial class MainWindow : Window {
        NwindDataSet.SalesPersonDataTable salesPersonDataTable = new NwindDataSet.SalesPersonDataTable();
        SalesPersonTableAdapter salesPersonDataAdapter = new SalesPersonTableAdapter();

        public MainWindow() {
            InitializeComponent();
            pivotGridControl1.DataSource = salesPersonDataTable;
        }

        private void Window_Loaded(object sender, RoutedEventArgs e) {
            salesPersonDataAdapter.Fill(salesPersonDataTable);
        }
    }
}

Imports Microsoft.VisualBasic
Imports System.Data
Imports System.Data.OleDb
Imports System.Windows
Imports DevExpress.Xpf.PivotGrid
Imports HowToBindToMDB.NwindDataSetTableAdapters

Namespace HowToBindToMDB
    ''' <summary>
    ''' Interaction logic for MainWindow.xaml
    ''' </summary>
    Partial Public Class MainWindow
        Inherits Window
        Private salesPersonDataTable As New NwindDataSet.SalesPersonDataTable()
        Private salesPersonDataAdapter As New SalesPersonTableAdapter()

        Public Sub New()
            InitializeComponent()
            pivotGridControl1.DataSource = salesPersonDataTable
        End Sub

        Private Sub Window_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
            salesPersonDataAdapter.Fill(salesPersonDataTable)
        End Sub
    End Class
End Namespace