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  • lambda表达式 巧用

    首先定义一个学生成绩类

    public class StudentResult
    {
        public int Id { get; set; }
        public string No { get; set; }
        public string Name { get; set; }
        public int Num { get; set; }
    }

    1、分页

    public ClassA()
    {
        int pageIndex = 1;int pageSize = 100;
        var tempList = new List<StudentResult>();
        var lastList = tempList.Skip((pageIndex-1)*pageSize).Take(pageSize).ToList();
    }

    2、聚合计算

    public List<StudentResult> GetGroupSum(List<StudentResult> list)
    {
        var tempList = list.GroupBy(v => new { v.Id, v.No, v.Name }).Select(o => new { keys = o.Key, tempNum = o.Sum(v => v.Num) }).ToList();
        var lastList = new List<StudentResult>();
        tempList.ForEach(v =>
        {
            lastList.Add(new StudentResult() { Id = v.keys.Id, No = v.keys.No, Name = v.keys.Name,Num = v.tempNum });
        });
        return lastList;
    }
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  • 原文地址:https://www.cnblogs.com/liangshibo/p/12198142.html
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