Building a Class within...but getting the typical error: "Object reference..."

[pstrusi]

Hi,
When I try to run the Algo, the typical error pops up: "Object reference not set to an instance of an object"
Posting here, just in case anyone in the forum might indicate what I'm doing wrong initializing the Class Trendline.
Thanks a lot!

namespace NinjaTrader.Strategy
{
    [Description("vvv")]

    public class Trendline
    {
        public int position;
        public double rate;

        public Trendline()  
        {
            position = 0;
            rate = 0.00;
        }
    }

    public class VVV : Strategy
    {
        #region Variables    
        private Trendline[]             uptrend = new Trendline[1];
        private Trendline[]           downtrend = new Trendline[1];      
        #endregion

        protected override void Initialize()
        {
            Do stuff
        }
        protected override void OnStartUp()
        {
            uptrend = new Trendline[activedays + 1];
            downtrend = new Trendline[activedays + 1];
        }

        protected override void OnBarUpdate()                                        
        {    
            if ( CurrentBar < 1 )
            {
                for (int i = 0; i < activedays; i++)
                {            
                    uptrend[i] = new Trendline();
                    downtrend[i] = new Trendline();
                }
                for (int i = 0; i < activedays; i++)
                {            
                    uptrend[i].position = 0;
                    uptrend[i].rate = 0.00;
                    downtrend[i].position = 0;
                    downtrend[i].rate = 0.00;
                }
            }

[pstrusi]

I've been able to solve the error by doing this modification:

namespace NinjaTrader.Strategy
{
    [Description("vvv")]

    public class Trendline
    {
        public int position;
        public double rate;

        public Trendline()  
        {
            position = 0;
            rate = 0.00;
        }
    }

    public class VVV : Strategy
    {
        #region Variables    
        private Trendline[]             uptrend = new Trendline[1];
        private Trendline[]           downtrend = new Trendline[1];      
        #endregion

        protected override void Initialize()
        {
            Do stuff
        }
        protected override void OnStartUp()
        {
            uptrend = new Trendline[activedays + 1];
            downtrend = new Trendline[activedays + 1];
            for (int i = 0; i < activedays; i++)
                {            
                    uptrend[i] = new Trendline();
                    downtrend[i] = new Trendline();
                }
        }

        protected override void OnBarUpdate()                                        
        {    
            if ( CurrentBar < 1 )
            {

                for (int i = 0; i < activedays; i++)
                {            
                    uptrend[i].position = 0;
                    uptrend[i].rate = 0.00;
                    downtrend[i].position = 0;
                    downtrend[i].rate = 0.00;
                }
            }