How to apply gradient color for OLAP Chart series in Silverlight?

public partial class MainPage : UserControl
    {
        private IOlapDataProvider dataProvider;
        public object OlapDataManager;
        public MainPage()
        {
            InitializeComponent();
            InitializeConnection();
this.olapchart1.Loaded += new RoutedEventHandler(olapchart1_Loaded);
        }
        private void InitializeConnection()
        {
            Binding customBinding = new CustomBinding(new BinaryMessageEncodingBindingElement(), new HttpTransportBindingElement { MaxReceivedMessageSize = 2147483647 });
            EndpointAddress address = new EndpointAddress("http://bi.syncfusion.com/OlapWcfProject/Services/OlapManager.svc/binary");
            ChannelFactory<IOlapDataProvider> clientChannel = new ChannelFactory<IOlapDataProvider>(customBinding, address);
            dataProvider = clientChannel.CreateChannel();
            OlapDataManager olapDataManager = new OlapDataManager();
            olapDataManager.DataProvider = dataProvider;
            olapDataManager.SetCurrentReport(CreateOlapReport());
            this.OlapDataManager = olapDataManager;
        }
void olapchart1_Loaded(object sender, RoutedEventArgs e)
        {
            GradientStopCollection stopCollection = new GradientStopCollection();
            GradientStop stop1 = new GradientStop();
            stop1.Color = Colors.Gray;
            stop1.Offset = 0.0;
            stopCollection.Add(stop1);
            GradientStop stop2 = new GradientStop();
            stop2.Color = Colors.Magenta;
            stop2.Offset = 1.0;
            stopCollection.Add(stop2);
            LinearGradientBrush linearGradiBrush = new               LinearGradientBrush(stopCollection, 45.00);
            foreach (var series in olapchart1.OlapChartArea.Series)
            {
                foreach (var seg in series.Segments)
                {
                    seg.Interior = linearGradiBrush;
                }
            }
        }

    Partial Public Class MainPage
    Inherits UserControl
    Private dataProvider As IOlapDataProvider
    Public OlapDataManager As Object
    Public Sub New()
        InitializeComponent()
        InitializeConnection()
Me.olapchart1.Loaded += New RoutedEventHandler(olapchart1_Loaded)
    End Sub
    Private Sub InitializeConnection()
            Binding customBinding = New CustomBinding(New BinaryMessageEncodingBindingElement(), New HttpTransportBindingElement 
            {
        MaxReceivedMessageSize = 2147483647
            }
)
        Dim address As EndpointAddress = New EndpointAddress("http://bi.syncfusion.com/OlapWcfProject/Services/OlapManager.svc/binary")
        Dim clientChannel As ChannelFactory<IOlapDataProvider> =  New ChannelFactory<IOlapDataProvider>(customBinding,address) 
        dataProvider = clientChannel.CreateChannel()
        Dim olapDataManager As OlapDataManager = New OlapDataManager()
        olapDataManager.DataProvider = dataProvider
        olapDataManager.SetCurrentReport(CreateOlapReport())
        Me.OlapDataManager = olapDataManager
    End Sub
Private Sub olapchart1_Loaded(ByVal sender As Object, ByVal e As RoutedEventArgs)
Dim stopCollection As GradientStopCollection = New GradientStopCollection()
    Dim stop1 As GradientStop = New GradientStop()
            stop1.Color = Colors.Gray
            stop1.Offset = 0.0
            stopCollection.Add(stop1)
    Dim stop2 As GradientStop = New GradientStop()
            stop2.Color = Colors.Magenta
            stop2.Offset = 1.0
            stopCollection.Add(stop2)
    Dim linearGradiBrush As LinearGradientBrush = New LinearGradientBrush(stopCollection, 45.0)
        Dim series As var
        For Each series In olapchart1.OlapChartArea.Series
            Dim seg As var
            For Each seg In series.Segments
                seg.Interior = linearGradiBrush
            Next
        Next
End Sub