C# ColorLine not showing up in TChart

Question

I currently have an TChart where I want to introduce a draggable horizontal line which changes the color of the points below the line. I have chosen to use ColorLine for this purpose but the line does not appear in the TChart. Am I using the right TChart tool for the job or am I missing something?

Below is the stripped down version of my current code.

public class testClass
{
    private ColorLine line;
    private double lineYVal = 5;
    private TChart savedChart;

    public testClass()
    {
        line = new Colorline();
        line.AllowDrag = true;
        line.Pen.Color = Color.Red;
        line.EndDragLine += lineDragHandler;
    }

    public void foo(TChart chart)          //chart is prepopulated with datapoints from 0->10
    {
        savedChart = chart;
        //existing code which assigns colors
        chart.Series[0].ColorRange(chart.Series[0].YValues, double.MinValue, lineYVal, Color.Red);
        chart.Series[0].ColorRange(chart.Series[0].YValues, lineYVal, double.MaxValue, Color.Blue);

        //my attempt to add a line
        chart.Tools.Add(line);
        line.Active = true;
        line.Axis = chart.Axes.Left;
        line.Value = lineYVal;
    }

    private void lineDragHandler(object sender)
    {
        lineYVal = line.Value;
        savedChart.Tools.Clear();     //remove existing line from chart
        foo(savedChart);              //redo colors and re-add line
    }
}

Answer 1

It turns out that while the line was being added correctly, the code I was using to display the chart was not updating the chart properly and was displaying a version of the chart from before it was passed into my highlight function.

Answer 2

Code below works fine for me here. If your problem persists please send a Short, Self Contained, Correct (Compilable), Example project to reproduce the problem here. You can post your files at www.steema.net/upload.

using Steema.TeeChart;
using Steema.TeeChart.Styles;
using Steema.TeeChart.Tools;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
  public partial class Form1 : Form
  {
    public Form1()
    {
      InitializeComponent();
      InitializeChart();
    }

    private void InitializeChart()
    {
      testClass();

      //existing code which assigns colors
      tChart1.Series.Add(new Steema.TeeChart.Styles.Bar()).FillSampleValues();

      tChart1.Series[0].ColorRange(tChart1.Series[0].YValues, double.MinValue, lineYVal, Color.Red);
      tChart1.Series[0].ColorRange(tChart1.Series[0].YValues, lineYVal, double.MaxValue, Color.Blue);

      //my attempt to add a line
      tChart1.Tools.Add(line);
      line.Active = true;
      line.Axis = tChart1.Axes.Left;
      line.Value = lineYVal;
    }

    private ColorLine line;
    private double lineYVal = 5;
    private TChart savedChart;

    public void testClass()
    {
      line = new ColorLine();
      line.AllowDrag = true;
      line.Pen.Color = Color.Red;
      line.EndDragLine += lineDragHandler;
    }

    public void foo(TChart chart)          //chart is prepopulated with datapoints from 0->10
    {
      savedChart = chart;
      //existing code which assigns colors
      chart.Series[0].ColorRange(chart.Series[0].YValues, double.MinValue, lineYVal, Color.Red);
      chart.Series[0].ColorRange(chart.Series[0].YValues, lineYVal, double.MaxValue, Color.Blue);

      //my attempt to add a line
      chart.Tools.Add(line);
      line.Active = true;
      line.Axis = chart.Axes.Left;
      line.Value = lineYVal;
    }

    private void lineDragHandler(object sender)
    {
      lineYVal = line.Value;
      if (savedChart != null)
      {
        savedChart.Tools.Clear();   //remove existing line from chart
        foo(savedChart);              //redo colors and re-add line
      }
      else
      {
        foo(tChart1);
      }
    }

  }
}