PieSeries2D Class

<Window x:Class="PieDonut2DChart.Window1" 
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" 
        xmlns:dxc="http://schemas.devexpress.com/winfx/2008/xaml/charts" 
        xmlns:local="clr-namespace:PieDonut2DChart" 
        Title="Window1" Height="470" Width="700">
    <Window.DataContext>
        <local:ChartViewModel/>
    </Window.DataContext>
    <Grid>
        <dxc:ChartControl Name="chartControl">
            <dxc:SimpleDiagram2D>
                <dxc:PieSeries2D x:Name="series" 
                                 DisplayName="Sales" 
                                 DataSource="{Binding Path=Data}" 
                                 ArgumentDataMember="Argument" 
                                 ValueDataMember="Value" 
                                 LabelsVisibility="True" 
                                 LegendTextPattern="{}{A}: {V}" 
                                 HoleRadiusPercent="50">
                    <!--region #Model-->
                    <dxc:PieSeries2D.Model>
                        <dxc:GlarePie2DModel/>
                    </dxc:PieSeries2D.Model>
                    <!--endregion #Model-->
                    <dxc:PieSeries2D.TotalLabel>
                        <dxc:PieTotalLabel TextPattern="Total:&#x0a;{TV}"/>
                    </dxc:PieSeries2D.TotalLabel>
                    <dxc:PieSeries2D.Label>
                        <dxc:SeriesLabel TextPattern="{}{VP:P}" 
                                         dxc:PieSeries.LabelPosition="TwoColumns"/>
                    </dxc:PieSeries2D.Label>
                </dxc:PieSeries2D>
            </dxc:SimpleDiagram2D>
            <dxc:ChartControl.Legends>
                <dxc:Legend>
                    <dxc:Legend.Title>
                        <dxc:LegendTitle Content="Units Sold"/>
                    </dxc:Legend.Title>
                </dxc:Legend>
            </dxc:ChartControl.Legends>
        </dxc:ChartControl>
    </Grid>
</Window>

using System.Collections.ObjectModel;
using System.Windows;

namespace PieDonut2DChart {
    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();
        }
    }
    public class ChartViewModel {
        public Collection<DataPoint> Data { get; private set; }
        public ChartViewModel() {
            Data = new Collection<DataPoint> {
                        new DataPoint ("Bikes", 142345),
                        new DataPoint ("Accessories", 266344),
                        new DataPoint ("Components", 631359),
                        new DataPoint ("Clothing", 120007)
            };
        }
        public class DataPoint {
            public string Argument { get; private set; }
            public double Value { get; private set; }
            public DataPoint(string argument, double value) {
                Argument = argument;
                Value = value;
            }
        }
    }
}

Imports System.Collections.ObjectModel
Imports System.Windows

Namespace PieDonut2DChart
    Partial Public Class Window1
        Inherits Window

        Public Sub New()
            InitializeComponent()
        End Sub 
    End Class 
    Public Class ChartViewModel
        Private privateData As Collection(Of DataPoint)
        Public Property Data() As Collection(Of DataPoint)
            Get 
                Return privateData
            End Get 
            Private Set(ByVal value As Collection(Of DataPoint))
                privateData = value
            End Set 
        End Property 
        Public Sub New()
            Data = New Collection(Of DataPoint) From { _
                New DataPoint("Bikes", 142345), _
                New DataPoint("Accessories", 266344), _
                New DataPoint("Components", 631359), _
                New DataPoint("Clothing", 120007) _
            }
        End Sub 
        Public Class DataPoint
            Private privateArgument As String 
            Public Property Argument() As String 
                Get 
                    Return privateArgument
                End Get 
                Private Set(ByVal value As String)
                    privateArgument = value
                End Set 
            End Property 
            Private privateValue As Double 
            Public Property Value() As Double 
                Get 
                    Return privateValue
                End Get 
                Private Set(ByVal value As Double)
                    privateValue = value
                End Set 
            End Property 
            Public Sub New(ByVal argument As String, ByVal value As Double)
                Me.Argument = argument
                Me.Value = value
            End Sub 
        End Class 
    End Class 
End Namespace