how to make just one trade a day?

I tested the lines of code below.
in order to make only one trade per day, but the bot keeps making several trades a day. How can I solve this problem?

using System;
using System.Linq;
using cAlgo.API;
using cAlgo.API.Indicators;
using cAlgo.API.Internals;
using cAlgo.Indicators;

namespace cAlgo.Robots
{
    [Robot(TimeZone = TimeZones.ESouthAmericaStandardTime, AccessRights = AccessRights.None)]
    public class bot : Robot
    {
        [Parameter(DefaultValue = 0.0)]
        public double Parameter { get; set; }

        [Parameter("Source")]
        public DataSeries Source { get; set; }

        [Parameter("Volume", DefaultValue = 10000, MinValue = 1000)]
        public int Volume { get; set; }

        [Parameter("Stop Loss (pips)", DefaultValue = 35, MinValue = 10)]
        public double StopLoss { get; set; }

        [Parameter("Take_Profit", DefaultValue = 30, MinValue = 10)]
        public double TakeProfit { get; set; }

        [Parameter("Start Time", DefaultValue = 7.0)]
        public double StartTime { get; set; }

        [Parameter("Stop Time", DefaultValue = 16.0)]
        public double StopTime { get; set; }


        DateTime _lastTrade;

        private DateTime _startTime;
        private DateTime _stopTime;

        private RelativeStrengthIndex _1hrsi1;
        private StochasticOscillator _hstoch1;

        protected override void OnStart()
        {
            _startTime = Server.Time.Date.AddHours(StartTime);


            _stopTime = Server.Time.Date.AddHours(StopTime);


            _lastTrade = Server.Time.AddDays(-1);
        }

        protected override void OnTick()
        {

            var hour1 = MarketData.GetBars(TimeFrame.Hour);
            var day = Server.Time.DayOfWeek;

_1hrsi1 = Indicators.RelativeStrengthIndex(hour1.ClosePrices, 80);
            _hstoch1 = Indicators.StochasticOscillator(hour1, 80, 3, 80, MovingAverageType.Simple);

 if (Trade.IsExecuting)
                return;

            var currentHours = Server.Time.TimeOfDay.TotalHours;
            bool tradeTime = StartTime < StopTime ? currentHours > StartTime && currentHours < StopTime : currentHours < StopTime || currentHours > StartTime;

            if (!tradeTime)
                return;
            if (_1hrsi1.Result.LastValue > 75) if (_lastTrade.DayOfYear != Server.Time.DayOfYear)
                                            if (day == DayOfWeek.Monday || day == DayOfWeek.Tuesday || day == DayOfWeek.Wednesday || day == DayOfWeek.Thursday)
                                                if (Positions.Count == 0)
                                                    _lastTrade = Server.Time;

            ExecuteMarketOrder(TradeType.Buy, Symbol, Volume, "bot", StopLoss, TakeProfit);