LINQ查询具有多个条件并将值设置为列表

Question

Im working on a project at the moment which I am working with xml c# and line queries.

The main aim of this functions is to create A list of dates, with the total distance covered on each date (across all drivers), sorted by date (note that dates are formatted as YYYY/MM/YY to make sorting easier)

The only part I am unsure about is the last part where I'm sorting by date as I can only sort by distance at the moment.

public List<String> CalculateDistDates()
    {
        List<String> distDatesList = new List<string>();

        var datesDistTot =
            from Driver in this.Drivers
            from Journey in Driver.Journeys
            group Journey by Journey.JourneyDate into distance
            let totaldistance = (from jour in distance
            select (int)jour.Distance).Sum() 
            orderby totaldistance descending


            select new
            {
                journeyDate = .Key,
                totaldistance = totaldistance

            };

Answer 1

Tried to answer your question and tweaked code little bit to achieve the same result.

Mock Models

 public class Journey
    {
        public decimal Distance { get; set; }
        public DateTime JourneyDate { get; set; }
    }
    public class Drivers
    {
        public string Name { get; set; }
        public Journey Journey { get; set; }
    }

    public class  DistanceCovered
    {
        public DateTime JourneyDate { get; set; }
        public decimal TotalDistance { get; set; }
    }

Here is the function created in console app, just remove test code and fill it with your data.

public static void CalculateDistDates()
    {            
        var drivers = new List<Drivers>
        {
            new Drivers{Journey = new Journey {Distance = 1.2M, JourneyDate = DateTime.Now.AddDays(1).Date}},
            new Drivers{Journey =  new Journey{Distance = 1.2M, JourneyDate = DateTime.Now.AddDays(2).Date}},
            new Drivers{Journey =  new Journey{Distance = 1.1M, JourneyDate = DateTime.Now.AddDays(2).Date}},
            new Drivers{Journey =  new Journey{Distance = 1.5M, JourneyDate = DateTime.Now.AddDays(3).Date}},
            new Drivers{Journey = new Journey {Distance = 1.7M, JourneyDate = DateTime.Now.AddDays(-1).Date}},
            new Drivers{Journey =  new Journey{Distance = 1.1M, JourneyDate = DateTime.Now.AddDays(3).Date}},
            new Drivers{Journey =  new Journey{Distance = 0.2M, JourneyDate = DateTime.Now.AddDays(2).Date}}
        };

        var totalDistance = (from d in drivers
            group d by d.Journey.JourneyDate
            into j                 
            select new DistanceCovered
            {
                JourneyDate = j.Key,
                TotalDistance = j.Sum(r=>r.Journey.Distance)
            }).ToList().OrderBy(r=>r.JourneyDate).ThenByDescending(r=>r.TotalDistance);

        foreach (var t in totalDistance)
        {
            Console.WriteLine($"{t.JourneyDate}: {t.TotalDistance}" );
        }

        Console.ReadLine();            
    }