private void ultraChart1_FillSceneGraph(object sender, Infragistics.UltraChart.Shared.Events.FillSceneGraphEventArgs e)

{

    //gets the X and Y axis

    IAdvanceAxis x = (IAdvanceAxis)e.Grid["X"];

    IAdvanceAxis y = (IAdvanceAxis)e.Grid["Y"];

    //checks if axis exist

    if (x != null)

    {

        //figures out the coordinate to draw

        //a line at y=100

        int target = 100;

        int yVal = (int)y.Map(target);

        //note: the x axis is a string axis

        //that means that 0 stands for the first

        //column and 50 stands for the 50th

        //column               

        int xStart = (int)x.Map(0);

        int xEnd = (int)x.Map(50);

        //creates the line primitive based

        //on the coordinates

        Line l = new Line(new Point(xStart, yVal), new Point(xEnd, yVal));

        //sets the color of the line

        l.PE.Stroke = Color.Red;

        //adds it to the scene

        e.SceneGraph.Add(l);

    }

}