XAML:
xmlns:tk="clr-namespace:System.Windows.Controls.DataVisualization.Charting;assembly=System.Windows.Controls.DataVisualization.Toolkit"
Title="One Line" Height="350" Width="525" Loaded="Window_Loaded">
CS:
using System.Windows.Controls.DataVisualization.Charting;
private void Window_Loaded(object sender, RoutedEventArgs e) {
mcChart.LegendTitle = "Legend";
((LineSeries)mcChart.Series[0]).ItemsSource =
new KeyValuePair[]{
new KeyValuePair(DateTime.Now, 100),
new KeyValuePair(DateTime.Now.AddMonths(1), 130),
new KeyValuePair(DateTime.Now.AddMonths(2), 150),
new KeyValuePair(DateTime.Now.AddMonths(3), 125),
new KeyValuePair(DateTime.Now.AddMonths(4),155) };
}