c# - 使用 distinct 删除重复项

Question

我有一个类

class ShipmentsComparer : IEqualityComparer<Routes>
    {
        public bool Equals(Routes route1, Routes route2) =>
           route1.DockCode == route2.DockCode
           && route1.CarrierArrival == route2.CarrierArrival;

        public int GetHashCode(Routes obj) =>
        obj.DockCode.GetHashCode() ^ (obj.CarrierArrival.GetHashCode() * 13);
    }

和一个 IEnumerable

public IEnumerable <Shipments> Shipments
        {
            get
            {
                Debug.Print("Initiated");
                
                foreach (var item in Loads)
                {
                    if (item.ShipTo.Contains(" "))
                    {

                        foreach (var item2 in Routes.Where(d => d.DockCode == item.ShipTo.Substring(0, item.ShipTo.IndexOf(" ")) && d.CarrierDeparture.TimeOfDay == item.ShipTime.TimeOfDay).Distinct(new ShipmentsComparer()))
                        {
                                yield return new Shipments() { Arrival = item2.CarrierArrival, Departure = item2.CarrierDeparture, Issuer = item.Customer, Destination = item.ShipTo, LoadType = item.LoadType };
                        }
                    }
                }
            }
        }

删除重复值，但我仍然在此处显示的项目源中得到重复值:

我怎样才能让它只显示每个承运人的到达时间之一？

Answer 1

似乎您正在获得重复项，因为您仅“区分”了内部循环结果。您需要使用 Distinct在调用方 - Shipmetns.Distinct(new ShipmentsComparer())或者如果你想在属性中过滤它们，你可以使用 HashSet :

class ActuallyShipmentsComparer : IEqualityComparer<Shipments>
{
   //your logic
}

    public IEnumerable <Shipments> Shipments
    {
        get
        {
            Debug.Print("Initiated");
            var hash = new HashSet<Shipments>(new ActuallyShipmentsComparer());               
            foreach (var item in Loads)
            {
                if (item.ShipTo.Contains(" "))
                {
                    foreach (var item2 in Routes.Where(d => d.DockCode == item.ShipTo.Substring(0, item.ShipTo.IndexOf(" ")) && d.CarrierDeparture.TimeOfDay == item.ShipTime.TimeOfDay).Distinct(new ShipmentsComparer()))
                    {
                            var shipments = new Shipments { Arrival = item2.CarrierArrival, Departure = item2.CarrierDeparture, Issuer = item.Customer, Destination = item.ShipTo, LoadType = item.LoadType };
                            if(hash.Add(shipments))
                            {
                                yield return shipments;
                            }
                         
                    }
                }
            }
        }
    }

或者用 Routes 试试同样的方法如果它们足以确定出货量相等:

    public IEnumerable<Shipments> Shipments
    {
        get
        {
            Debug.Print("Initiated");
            var hash = new HashSet<Routes>(new ShipmentsComparer()); // rename ShipmentsComparer cause it is actually RoutesComparer             
            foreach (var item in Loads)
            {
                if (item.ShipTo.Contains(" "))
                {
                    foreach (var item2 in Routes.Where(d => d.DockCode == item.ShipTo.Substring(0, item.ShipTo.IndexOf(" ")) && d.CarrierDeparture.TimeOfDay == item.ShipTime.TimeOfDay))
                    {
                        if(hash.Add(item2))
                        {
                            yield return new Shipments { Arrival = item2.CarrierArrival, Departure = item2.CarrierDeparture, Issuer = item.Customer, Destination = item.ShipTo, LoadType = item.LoadType };
                        }                             
                    }
                }
            }
        }
    }