the following code demonstrates one technique for mouse dragging the datapoints in a line chart. 

for simplicity, it uses the FillSceneGraph event which was added in 7.3.  so if you want to use this in 7.2 or earlier, you'll have to implement ILayer as described in these topics: http://help.infragistics.com/Help/NetAdvantage/NET/2007.2/CLR2.0/html/Chart_Layers.html

using System;

using Infragistics.Win.UltraWinChart;

using System.Windows.Forms;

using System.Data;

using Infragistics.UltraChart.Resources.Appearance;

using Infragistics.UltraChart.Core.Primitives;

using Infragistics.UltraChart.Shared.Events;

using Infragistics.UltraChart.Shared.Styles;

using Infragistics.UltraChart.Core.Layers;

using Infragistics.UltraChart.Core;

using System.Drawing;

public partial class Form1 : Form

private UltraChart UltraChart1 { get; set; }

private IAdvanceAxis AxisY { get; set; }

private Primitive DraggingPrimitive { get; set; }

private Point MouseDownPoint { get; set; }

this.UltraChart1.Dock = DockStyle.Fill;

NumericSeries series1 = new NumericSeries();

series1.Points.Add(new NumericDataPoint(2.0, "Point B", false));

series1.Points.Add(new NumericDataPoint(4.0, "Point D", false));

this.UltraChart1.ChartType = ChartType.LineChart;

this.UltraChart1.MouseDown += new MouseEventHandler(UltraChart1_MouseDown);

this.UltraChart1.MouseLeave += new EventHandler(UltraChart1_MouseLeave);

// clear the draggingprimitive property to terminate the drag operation

// clear the draggingprimitive property to terminate the drag operation

// save the mousedown location for use in the FillSceneGraph handler.

// invalidate the chart so FillSceneGraph will be raised.

// store the Y axis as a property of this form.

// loop through the scenegraph.

// we found a polyline. examine its points to see if one is hit given the current mouse point.

// we found a point which matches our mouse point. store it as DraggingPrimitive.

// if DraggingPrimitive is not null, a drag is in progress.

// get the datapoint off the primitive

// change the datapoint value and invalidate the chart.