<c1chart:C1Chart x:Name="chart">

   <c1chart:C1Chart.Resources>

      <DataTemplate x:Key="tt">

        <StackPanel Orientation="Vertical">

          <!-- XAsString returns xvalue that is formatted similar to x-axis -->

          <TextBlock Text="{Binding XAsString}" />

          <TextBlock Text="{Binding Y}" />

        </StackPanel>

      </DataTemplate>

    </c1chart:C1Chart.Resources>

</c1chart:C1Chart>

Dim cnt As Integer = 20

Dim x As DateTime() = New DateTime(cnt - 1) {}

Dim y As Double() = New Double(cnt - 1) {}

Dim rnd As New Random()

For i As Integer = 0 To cnt - 1

    x(i) = DateTime.Today.AddDays(-i)

    y(i) = rnd.NextDouble() * 100

Next

chart.Data.Children.Add(New XYDataSeries())

chart.View.AxisX.IsTime = True

chart.ChartType = ChartType.LineSymbols

int cnt = 20;

  DateTime[] x = new DateTime[cnt];

  double[] y = new double[cnt];

  Random rnd = new Random();

  for (int i = 0; i < cnt; i++)

  {

     x[i] = DateTime.Today.AddDays(-i);

     y[i] = rnd.NextDouble() * 100;

  }

  chart.Data.Children.Add(new XYDataSeries()

  {

     XValuesSource = x, ValuesSource = y,

     PointTooltipTemplate = (DataTemplate)chart.Resources["tt"]

  });

  chart.View.AxisX.IsTime = true;

  chart.ChartType = ChartType.LineSymbols;