can this line be drag when the mouse down?

if it can, how to do that?

thanks for your reply.

You will have to handle a combination of MouseMove, DataItemOver/Out, MouseDown/Up events to accomplish this.

public int XCoord { get; set; }
public bool IsMouseDown { get; set; }
public bool IsMouseOver { get; set; }
private NumericDataPoint point = new NumericDataPoint(0, "", true);

private void ultraChart1_FillSceneGraph(object sender, Infragistics.UltraChart.Shared.Events.FillSceneGraphEventArgs e)
{
 if (e.Grid.Count == 0) return;
  
 Rectangle bounds = e.ChartCore.GridLayerBounds;
 int x = XCoord;
 if (x < bounds.Left)
 {
  x = bounds.Left;
 }
 if (x>bounds.Right)
 {
  x = bounds.Right;
 }
 
 Box line = new Box(new Rectangle(x, bounds.Top, 2, bounds.Height));
 line.PE.Stroke = line.PE.Fill = Color.Black;
 line.PE.StrokeWidth = 1;
 line.Row = line.Column = 0;
 line.Caps = PCaps.HitTest | PCaps.Tooltip;
 line.Layer = e.ChartCore.GetChartLayer();
 line.Chart = ChartType.ColumnChart;
 line.Value = "myline";

 line.DataPoint = point;

 e.SceneGraph.Add(line);
}

private void Form1_Load(object sender, EventArgs e)
{
 ultraChart1.ChartType = ChartType.ColumnChart;
 ultraChart1.Data.DataSource = DemoTable.Table();
 XCoord = 150;
}

private void ultraChart1_DataItemOver(object sender, Infragistics.UltraChart.Shared.Events.ChartDataEventArgs e)
{
 if (e.Primitive is Box && e.Primitive.DataPoint == point)
 {
  IsMouseOver = true;
 }
}

private void ultraChart1_DataItemOut(object sender, Infragistics.UltraChart.Shared.Events.ChartDataEventArgs e)
{
 IsMouseOver = false;
}

private void ultraChart1_MouseDown(object sender, MouseEventArgs e)
{
 if (IsMouseOver) IsMouseDown = true;
 else IsMouseDown = false;
}

private void ultraChart1_MouseUp(object sender, MouseEventArgs e)
{
 IsMouseDown = false;
}

private void ultraChart1_MouseMove(object sender, MouseEventArgs e)
{
 if (IsMouseDown)
 {
  XCoord = e.X;
  ultraChart1.InvalidateLayers();
 }
}