c# - 如何先按一个属性排序，然后再按另一个属性排序，而不考虑第一个属性的关系？

Question

我想要实现的是首先按最高 Amount 对 OrderSummary 进行排序，然后显示集合中的所有其他 Order无论 Amount 一个接一个地为给定的帐户。预期结果在代码片段中..

 public class OrderSummary
    {
        public string FirstName { get; set; }

        public decimal Amount { get; set; }
    }

    public class Worker
    {
        public List<OrderSummary> Orders { get; set; }

        public Worker()
        {
            Orders = new List<OrderSummary>()
            {
                new OrderSummary() {FirstName = "James", Amount = 10.00m},
                new OrderSummary() {FirstName = "Thomas", Amount = 11.00m},
                new OrderSummary() {FirstName = "Leon", Amount = 13.00m},
                new OrderSummary() {FirstName = "Lori", Amount = 14.00m},
                new OrderSummary() {FirstName = "Thomas", Amount = 16.00m},
                new OrderSummary() {FirstName = "Thomas", Amount = 6.00m},
                new OrderSummary() {FirstName = "James", Amount = 19.00m}
            };
        }

        //sorted by highest amount first
        //then place firstname together regardless of the amount

        //Expected Outcome
        /*
           James 19 -- highest amount followed by all other orders for James regardless of the amount.
         * james 10
         * thomas 16
         * thomas 11
         * thomas 6
         * lori 14
         * leon 13
         */
    }

我的方法是获取所有出现不止一次的元素，然后定位除第一个元素外的元素在哪个索引处，将其从索引中移除，并将其添加到第一个元素的索引 + 1.. 是否有更好的方法来完成这个？

Answer 1

GroupBy 按照它们在源集合中出现的顺序创建组，因此您可以先按数量排序，然后按名称分组，然后“展平”组:

var results = Orders.OrderByDescending(o => o.Amount)
                    .GroupBy(o => o.FistName)  // the groupings will be in order of the largest amount
                    .SelectMany(g => g);       // flatten the groups