Hi,

The SelectedObject property from HitTestArgs is null if mouse is not above a DataPoint (Series). Only when data points are selected the SelectedObject will return a reference to a data point. This example shows how selection works:

C#:

using System;
using System.IO;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Navigation;
using Infragistics.Windows.Chart;

namespace UntitledProject8
{
 public partial class Window1
 {
  public Window1()
  {
            this.InitializeComponent();
   
   // Insert code required on object creation below this point.
  }

        protected override void OnMouseDown(System.Windows.Input.MouseButtonEventArgs e)
        {
            HitTestArgs args = this.Chart1.HitTest(e);
            base.OnMouseDown(e);
        }
 }
}

XAML:

<Window
 xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
 xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
 xmlns:igCA="http://infragistics.com/Chart"
 x:Class="UntitledProject8.Window1"
 x:Name="Window"
 Title="Window1"
 Width="640" Height="480">

 <Grid x:Name="LayoutRoot">
  <igCA:XamChart Name="Chart1" Margin="8,8,8,8">
   <igCA:XamChart.Series>
    <igCA:Series>
     <igCA:Series.DataPoints>
      <igCA:DataPoint Value="2"/>
      <igCA:DataPoint Value="8"/>
      <igCA:DataPoint Value="6"/>
      <igCA:DataPoint Value="7"/>
     </igCA:Series.DataPoints>
    </igCA:Series>
   </igCA:XamChart.Series>
  </igCA:XamChart>
 </Grid>
</Window>

• DataPointTemplate - The base class that xamChart uses for applicable DataPoints.
• AreaChartTemplate - The xamChart control uses this class for the following chart types:
  • Area
  • Stacked Area
  • Stacked 100 Area
• BubbleChartTemplate - The xamChart control uses this class for the Bubble Chart.
• BarChartTemplate - The xamChart control uses this class for the following chart types:
  • Bar
  • Stacked Bar
  • Stacked 100 Bar
  • Cylinder Bar
  • Stacked Cylinder Bar
  • Stacked 100 Cylinder Bar
• ColumnChartTemplate - The xamChart control uses this class for the following chart types:
  • Column
  • Stacked Column
  • Stacked 100 Column
  • Cylinder
  • Stacked Cylinder
  • Stacked 100 Cylinder

There is nothing there about scatterline.