I am struggling here. The basicTemplateAlgorithm.cs seems running.

I add my own test file RollingWindow.cs and the debug F5 just gave a null reference exception .

public class QCURollingWindow : QCAlgorithm     {         RollingWindow<TradeBar> _window = new RollingWindow<TradeBar>(7);         public override void Initialize()         {             SetStartDate(2013, 10, 07);  //Set Start Date             SetEndDate(2013, 10, 11);             SetCash(25000);             AddSecurity(SecurityType.Equity, "SPY", Resolution.Minute);         }         public void OnData(TradeBars data)         {             //Inject data into the rolling window.             _window.Add(data["SPY"]);             if (!_window.IsReady) return;             if (_window[0].Close > _window[6].Close)             {                 SetHoldings("SPY", -0.5);                 Debug("Short Stock");             }             else {                 SetHoldings("SPY", 0.5);                 Debug("Purchased Stock");             }         }     }

I just copied the codes from tutorial and changed the dates as there's only four days' data.