How to change indicator value?

[clearpicks]

I use an indicator script to calculate some resistance and support lines every five minutes and draw them on the chart using DrawLine() and delete the old R/S lines at the same time. However if I click mouse on the chart to scroll the chart to the right, in most cases some line object would get selected and moved instead of the chart being scrolled, and I have to reload the indicators by pressing "F5". So I decide to use something like Add(new Line(MyColor, MyRSValue, "RSTag") to show the calculated R/S lines as horizontal lines. My question is how to change the MyRSValue in realtime to the calculated value? In those indicator script like pivot or rsi, the value is either set every tick/bar or set to a fixed value in intialize() function. What is the correct way to set my R/S lines? Your help is greatly appreciated.

- Clearpicks

[NinjaTrader_Ray]

Try something like this in OnBarUpdate()

Lines[0].Value = yourValue;

[clearpicks]

Ray,

What if I want to use Add(Plot plot) instead of using Add(Line line)? The lines drawn by Add(Line line) extend to the right of the last bar, which make them interfere with the lines drawn by ChartTrader. Is there a simple way to move the line drawn by Add(Plot plot) to different R/S value in realtime trading similar to
Lines[0].Value = yourValue;
you just taught me?

- Clearpicks

[NinjaTrader_JoshP]

Unfortunately not. You would have to dive into overriding the Plot method which is beyond the level we can support. We have on our list of considerations some improvements to the Draw() methods that may help alleviate this usage case though.

[KBJ]

Why couldn't you do something like this:

protected override void Initialize()
{
    Add(new Plot(Color.Magenta, PlotStyle.Line, "Sup")); // Plots[0]
    Add(new Plot(Color.Orange,  PlotStyle.Line, "Res")); // Plots[1]

    Overlay               = true;  // Display over price panel.
    PriceTypeSupported    = false; // Don't display price marker on right.
}

protected override void OnBarUpdate()
{
    //
    // Calculate new support value and save it as NewSup
    //

    for (int idx=0; idx < CurrentBar; idx++)  // Set all values of Sup plot.
        Plots[0].Set( idx, NewSup );
}

This should move the line to the new value every time you come up with a different value of "NewSup".

[NinjaTrader_JoshP]

Thanks KBJ. Worth a shot.