Using existing indicator value in custom indicator

[ActiveTrader09]

I am trying modify the existing Donchian Channel indicator so it uses the upper and lower Bollinger Band for the upper and lower channels. Right now I am using an indicator of an indicator for the upper and lower channels. I want one indicator to do what depicted in the attached chart. Thanks.

I have no scripting knowledge. I cut and pasted the following from other coding examples.

public class DonchianBands : Indicator
    {
        #region Variables
        private int            period        = 20;
        double upperValue = Bollinger(2, 20).Upper[0];
        double lowerValue = Bollinger(2, 20).Lower[0];
        #endregion

        /// <summary>
        /// This method is used to configure the indicator and is called once before any bar data is loaded.
        /// </summary>
        protected override void Initialize()
        {
            Add(new Plot(Color.Orange, "Mean"));
            Add(new Plot(Color.Blue, "Upper"));
            Add(new Plot(Color.Blue, "Lower"));

            Overlay            = true;
        }
        
        /// <summary>
        /// Called on each bar update event (incoming tick)
        /// </summary>
        protected override void OnBarUpdate()
        {
            Value.Set((MAX(upperValue, Period)[0] + MIN(lowerValue, Period)[0]) / 2);
            Upper.Set(MAX(upperValue, Period)[0]);
            Lower.Set(MIN(lowerValue, Period)[0]);
        }

[NinjaTrader_ChelseaB]

Hello ActiveTrader09,

The Bollinger() indicator cannot be called outside of a method.

The line:
double upperValue = Bollinger(2, 20).Upper[0];

will not compile.

Try the following instead:

Value.Set((MAX(Bollinger(2, 20).Upper[0], Period)[0] + MIN(Bollinger(2, 20).Lower[0], Period)[0]) / 2);

Or you can continue using the variables, but set these in OnBarUpdate on each bar before they are used.

[ActiveTrader09]

I replaced the code with the following and still get errors on compile. Like I said I am a complete newbie when it comes to coding anything. I attached the .cs file for reference. Thanks.

public class DonchianBands : Indicator
    {
        #region Variables
        private int            period        = 20;
        #endregion

        /// <summary>
        /// This method is used to configure the indicator and is called once before any bar data is loaded.
        /// </summary>
        protected override void Initialize()
        {
            Add(new Plot(Color.Orange, "Mean"));
            Add(new Plot(Color.Blue, "Upper"));
            Add(new Plot(Color.Blue, "Lower"));

            Overlay            = true;
        }
        
        /// <summary>
        /// Called on each bar update event (incoming tick)
        /// </summary>
        protected override void OnBarUpdate()
        {
            Value.Set((MAX(Bollinger(2, 20).Upper[0], Period)[0] + MIN(Bollinger(2, 20).Lower[0], Period)[0]) / 2);
            Upper.Set(MAX(Bollinger(2, 20).Upper[0], Period)[0]);
            Lower.Set(MIN(Bollinger(2, 20).Lower[0], Period)[0]);
        }

Hello ActiveTrader09,

The Bollinger() indicator cannot be called outside of a method.

The line:
double upperValue = Bollinger(2, 20).Upper[0];

will not compile.

Try the following instead:

Value.Set((MAX(Bollinger(2, 20).Upper[0], Period)[0] + MIN(Bollinger(2, 20).Lower[0], Period)[0]) / 2);

Or you can continue using the variables, but set these in OnBarUpdate on each bar before they are used.

[NinjaTrader_ZacharyG]

Hello ActiveTrader09,

Please take a look at the following overloads for MAX() and MIN():

MAX(IDataSeries input, int period);
MIN(IDataSeries input, int period);

You are attempting pass a double value into the parameter that accepts an IDataSeries object.

You will need to replace your code within OnBarUpdate() with:

Value.Set((MAX(Bollinger(2, 20).Upper, Period)[0] + MIN(Bollinger(2, 20).Lower, Period)[0]) / 2);
Upper.Set(MAX(Bollinger(2, 20).Upper, Period)[0]);
Lower.Set(MIN(Bollinger(2, 20).Lower, Period)[0]);

Please take a look at the following link on how methods function within C#: http://www.tutorialspoint.com/csharp/csharp_methods.htm

Please, let us know if we may be of further assistance.

[ActiveTrader09]

Zachary G.,

Thanks for your help, it worked like a charm!!!!

Surprisingly, I figured out how to use the standard deviation and period as a user defined variable.

Thanks again, it turned out exactly as expected.