实体框架 - 对列表中的行（几条记录）进行排序

Question

我有一个距离升序排列的列表。

like需要从4到6排序

未排序：

但我想这样排序， 在以距离方式排序后，现在想要根据可用性对列表进行排序，如果插槽如下所示 仅对相同距离的记录进行排序。

id从4到6排序

排序：

有没有人可以解决这个问题？

Answer 1

如果您真的只需要对完整列表中的数据块进行排序，那么我建议您使用以下方法之一将数据分组。

1. LINQ query — Data aggregation (Group Adjacent)
2. LINQ query to split an ordered list into sublists of contiguous points by some criteria
3. （推荐解决方案）https://github.com/morelinq/MoreLINQ/blob/master/MoreLinq/GroupAdjacent.cs https://www.nuget.org/packages/morelinq/

对于以下示例，我使用了第一个链接中所述的GroupAdjacent。

就这样吧：

//class for test data
public class Data
{
    public int    Id               { get; set; }
    public int    Distance         { get; set; }
    public string SlotAvailability { get; set; }

    public override string ToString()
    {
        return $"ID={Id} | Distance={Distance} | SlotAvailability={SlotAvailability}";
    }
}

class Program
{
    static void Main(string[] args)
    {
        //test data
        var lst = new List<Data>()
        {
            new Data() {Id = 1, Distance = 5, SlotAvailability  = "yes"},
            new Data() {Id = 2, Distance = 6, SlotAvailability  = "yes"},
            new Data() {Id = 3, Distance = 8, SlotAvailability  = "no"},
            new Data() {Id = 4, Distance = 9, SlotAvailability  = "no"},
            new Data() {Id = 5, Distance = 9, SlotAvailability  = "yes"},
            new Data() {Id = 6, Distance = 9, SlotAvailability  = "in future"},
            new Data() {Id = 7, Distance = 11, SlotAvailability = "in future"},
            new Data() {Id = 8, Distance = 9, SlotAvailability  = "in future"},
        };

        //group the results into chunks
        var groupedList = lst.GroupAdjacent(x => x.Distance)

        //apply the sort logic - this assumes that you only want to sort if there are more or equals to 3 items in the group
        var sortedList = groupedList.SelectMany(x =>
        {
            if (x.Count() < 3) //if the count of the group is below 3 return it as it is
                return x.AsEnumerable();

            //if the Count is greater or equals to 3 sort the Group by SlotAvailability
            return x.OrderBy(y =>
            {
                switch (y.SlotAvailability)
                {
                    case "yes":
                        return 1;
                    case "in future":
                        return 2;
                    case "no":
                        return 3;

                    default:
                        return 0;
                }
            });
        });

        //print result
        foreach (var data in sortedList)
            Console.WriteLine(data);

        //wait for user input
        Console.ReadKey();
    }
}

如果您不希望在有 3 个或更多项目的情况下应用 SlotAvailability 排序逻辑而不是使用它

var sortedList = groupedList.SelectMany(x => x.OrderBy(y =>
    {
        switch (y.SlotAvailability)
        {
            case "yes":
                return 1;
            case "in future":
                return 2;
            case "no":
                return 3;

            default:
                return 0;
        }
    }));

Answer 2

好的，我在这里假设您对SlotAvailability 的值是我们在表中看到的字符串。您可以权重 OrderBy 语句，以确保按照您的需要按yes, in future, no 排序。

结果将是您按Distance 升序然后按您的加权SlotAvailability 值（也是升序）对记录进行排序。

我还假设您只有 SlotAvailability 可能的这 3 个值

例如：

.OrderBy(n=>n.Distance).ThenBy(n=>n. SlotAvailability == "yes" ? 1 : (n. SlotAvailability == "no" ? 3 : 2));

如您所见，我是这样分配权重（以及顺序）的：

• 1 = 是
• 2 = 未来
• 3 = 否