protected override void OnStateChange()
{
    if (State == State.SetDefaults)
    {
        // Lines are added to the Lines collection in order
        AddLine(Brushes.Gray, 30, "Lower"); // Stored in Lines[0]
        AddLine(Brushes.Gray, 70, "Upper"); // Stored in Lines[1]
    }
}
 
// Dynamically change the upper line's color and thickness based on the indicator value
protected override void OnBarUpdate()
{
  if(Value[0] > 70)
  {
    Lines[1].Brush = Brushes.Blue;
    Lines[1].Width = 3;
  }
  else
  {
    Lines[1].Brush = Brushes.Gray;
    Lines[1].Width = 1;
  }
}