Getting error after position is closed

[investdatasystems]

Hello

I use the code hereafter, that opens a long position then closes this latter after the profit and loss reaches 100€.

When the PnL of 100€ is reached, the (account) position is well closed but I have an error that I
try to intercept with try/catch blocks in order for the strategy not to be disabled but it is still disabled after the error...

The error is :
Exception while trying to access Strategy Position : La référence d'objet n'est pas définie à une instance d'un objet.
**NT** Error on calling 'OnBarUpdate' method for strategy 'IchimokuExpertStrategy/682e1335e2244371ba1fae15d0be724c': La référence d'objet n'est pas définie à une instance d'un objet.


Thanks !

		double ask = 0;
		double bid = 0;
		double PnL = 0;
		DateTime dt = new DateTime();
		bool done = false;
        /// <summary>
        /// Called on each bar update event (incoming tick)
        /// </summary>
        protected override void OnBarUpdate()
        {
			dt = DateTime.Now;	
			
			Print("**** Account Positions ****");
			if (Account.Positions.Count>0)
			{
				for (int i=0;i<Account.Positions.Count;i++)
				{
					try
					{
						Print("Account Position " + i);
						Print(">> " + dt + " : Instrument Name = " + Account.Positions[i].Instrument.FullName);
						Print(">> " + dt + " : PnL = " + Account.Positions[i].GetProfitLoss(GetCurrentBid(), PerformanceUnit.Currency));
						Print(">> " + dt + " : Qty = " + Account.Positions[i].Quantity);
						double profit = Account.Positions[i].GetProfitLoss(GetCurrentBid(), PerformanceUnit.Currency);
						if (profit>=100)
						{
							Account.Positions[i].Close();
						}
					}
					catch(Exception ex)
					{
						Print("Exception while trying to access Account Position " + i + " : " + ex.Message);
					}
				}
			}
			
			try
			{
				Print("**** Strategy Position ****");
				PnL = Position.GetProfitLoss(GetCurrentBid(), PerformanceUnit.Currency);
				Print(">> " + dt + " : PnL =" + PnL);
				Print(">> " + dt + " : Qty =" + Position.Quantity);
			}
			catch(Exception ex)
			{
				[B][COLOR="lime"]Print("Exception while trying to access Strategy Position : " + ex.Message);[/COLOR][/B]
			}
						
			if (this.Historical == true) return;
			
			double ask = this.GetCurrentAsk();
			double bid = this.GetCurrentBid();
			if (done == false)
			{
				Print("Will enter long position");
				IOrder iorder = EnterLong(1000000);
				done = true;
			}			
			
			Print("");
        }

[investdatasystems]

I have just tried to put a try/catch block around all the code in the OnBarUpdate() overrided method but the Strategy is disabled also when the Index error is printed.

[investdatasystems]

Adding this condition seems to resolve my issue :

if (this.Positions.GetLength(0)>0)

I hope that will help

[NinjaTrader_Jesse]

Hello

Thank you for the post.

To start, I would not suggest using try/catch statements in ninjascript. The reason is that if you bypass an exception with a try/catch, you could allow the script to still try to execute other code in a bad state, the script should instead be stopped so you can correct the exception.

The error "Object reference not set to an instance of an object." means that an object you have used was null when you used it. As I cannot see the rest of the prints you are using I am not sure where this error would have come from during the execution of the script.

For this type of problem, instead of using a try catch, I would suggest using some Prints to see either where the logical execution stops or to print out the objects you use to know which is null.

In your current logic, you have prints already so you should have some output surrounding the exception. If you run the script without any try catch, it should be the last output before the script stopped which is helpful.

If you can post the output leading up to the exception that would be helpful as we may be able to compare where the prints stopped to narrow what logic to look at. Otherwise, you should be able to use the output from your prints to locate the problematic line and we could further review why that was null knowing what object it was.

I look forward to being of further assistance.

[investdatasystems]

Thank you for your reply.

I have resolved the issue by adding the following code before any further attempt to read the Strategy Position :

if (this.Positions.GetLength(0)>0){
if (this.Position.Quantity>0){

}
}

I'll also avoid using try/catch blocks then.

Thanks again !!!