Code to reproduce (WPF):

    private void InitializeChart()
    {
      tChart1.Series.Add(typeof(Points));
      tChart1[0].Add(3);
      tChart1[0].Add(13);
      tChart1.Axes.Left.SetMinMax(0, 10);
    }

    private void Button_Click(object sender, RoutedEventArgs e)
    {
      var xamlFormat = new XAMLFormat(tChart1.Chart);
      using (MemoryStream ms = new MemoryStream())
      {
        try
        {
          xamlFormat.Save(ms);
          MessageBox.Show("Ok", "Saving chart to memory stream");
        }
        catch (Exception ex)
        {
          Console.WriteLine(ex);
          MessageBox.Show($" {ex.Message}", "Error when saving chart to memory stream ");
        }
      }
    }