XAML:

    xmlns:tk="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit" 
    Title="One Pie" Height="350" Width="525" Loaded="Window_Loaded">
    <DockPanel LastChildFill="True">
        <tk:Chart Canvas.Top="80" Canvas.Left="10" Name="mcChart"  Background="LightSteelBlue">
            <tk:Chart.Series  >
                <tk:ColumnSeries  BorderThickness="1" Title=" Monthly Count1" IndependentValueBinding="{Binding Path=Key}" DependentValueBinding="{Binding Path=Value}" />
                <tk:ColumnSeries  BorderThickness="1" Title=" Monthly Count2" IndependentValueBinding="{Binding Path=Key}" DependentValueBinding="{Binding Path=Value}" />
            </tk:Chart.Series>
        </tk:Chart>
    </DockPanel>


CS:
using System.Windows.Controls.DataVisualization.Charting;

private void Window_Loaded(object sender, RoutedEventArgs e) {
     mcChart.LegendTitle = "Legend";

            mcChart.LegendTitle = "Legende";

            ColumnSeries cs1 = ((ColumnSeries)mcChart.Series[0]);
            cs1.ItemsSource =
        new KeyValuePair<String, int>[]{
        new KeyValuePair<String,int>("M1", 100),
        new KeyValuePair<String,int>("M2", 130),
        new KeyValuePair<String,int>("M3", 150),
        new KeyValuePair<String,int>("M4", 125),
        new KeyValuePair<String,int>("M5",155) };

            ColumnSeries cs2 = ((ColumnSeries)mcChart.Series[1]);
            cs2.ItemsSource =
        new KeyValuePair<String, int>[]{
        new KeyValuePair<String,int>("M6", 110),
        new KeyValuePair<String,int>("M7", 140),
        new KeyValuePair<String,int>("M8", 250),
        new KeyValuePair<String,int>("M9", 325),
        new KeyValuePair<String,int>("M10",155) };

}