In a program, I want to show a movie and the audience ratings at the same time. So I created a little movie player with a LineChart on it. During the movie plays, a slider moves from left to right. In order to illustrate the current position, I place a vertically line on the chart, which is on the same position as the slider.

The processing:
1. A timer control fires every 10 ms.
2. In the timer_tick event, I reposition the slider button and invalidate the chart (via InvalidateLayers)
3. InvalidateLayers causes the FillSceneGraph event.
4. Inside FillSceneGraph I paint a red line. Here the source code:

public void Chart_FillSceneGraph(object sender, Infragistics.UltraChart.Shared.Events.FillSceneGraphEventArgs e)
{
 IAdvanceAxis axisX = e.Grid["X"] as IAdvanceAxis;
 IAdvanceAxis axisY = e.Grid["Y"] as IAdvanceAxis;
 double dLength = (double)axisX.Maximum - (double)axisX.Minimum;
 int xStart = (int)axisX.Map((int)(dLength * _Movie_Track.Value / _Movie_Track.Maximum));
 int xEnd = xStart;
 int yStart = (int)axisY.Map(axisY.Minimum);
 int yEnd = (int)axisY.Map(axisY.Maximum);
 
 _targetLine = new Line(new Point(xStart, yStart), new Point(xEnd, yEnd));
 _targetLine.PE.Stroke = Color.Red;
 _targetLine.PE.StrokeWidth = 1;
 e.SceneGraph.Add(_targetLine);
}

It works ok, but with big data (3 series, each 30000 datapoints) it works quite slow (plobably due to the multiple InvalidateLayer calls). So my question:
Is this the recommended way to do this or is there another (faster) alternative?