如何在一个返回一个实体求某些列的最大值，最小值，平均值，求和呢？

        过去一直都是用的循环对比，没有进行归纳，或者就是最笨的办法

            var demos = new List<Demo>();foreach (var item in demos){var values = new List<decimal>();values.Add(item.v00);values.Add(item.v15);values.Add(item.v30);values.Add(item.v45);var demo = new Demo();demo.YC_ID = item.YC_ID;demo.DATA_MAX = values.Max();demo.DATA_MIN = values.Min();demo.DATA_AVG = values.Average();demo.DATA_TOTAL = values.Sum();demos.Add(demo);}

那怎么写会更简单便捷呢？而不是每次使用这个实体，我们都要进行循环比较呢？

好吧，直接贴图吧~~~

看不懂的记得补课。

        private class Demo{public string Id {get;set;}public decimal V00 { get; set; }public decimal V15 { get; set; }public decimal V30 { get; set; }public decimal V45 { get; set; }private List<decimal> decimals { get; set; }public Demo SetValue(){decimals = new List<decimal>() { V00, V15, V30, V45 };return this;}public decimal Max(){return decimals.Max();}public decimal Min(){return decimals.Min();}public decimal Avg(){return decimals.Average();}public decimal Total(){return decimals.Sum();}}

            var allDemos = new List<Demo>();var demos = GetDemos.GroupBy(r => new { r.Id}).Select(r => new Demo{YC_ID = r.Key.Id,V00 = r.Sum(y => y.V00),V15 = r.Sum(y => y.V15),V30 = r.Sum(y => y.V30),V45 = r.Sum(y => y.V45),}.SetValue()).ToList();foreach (var item in demos){var demo = new Demo();demo.Id = item.Id;demo.MAX = item.Max();demo.MIN = item.Min();demo.AVG = item.Avg();demo.TOTAL = item.Total();allDemos.Add(demo);}