Question

我在计算数据库中的唯一值时遇到问题我有用户表状态为Unknown = 0，In = 1，Out = 2，UnknownWasIn = 3，UnknownWasOut = 4，问题是我不知道因为我们对它进行了硬编码，所以在数据库中有这个值的查找表。我创建了课程StatusCounter

using System;
using System.Dynamic;

public  class StatusCounter
{
    public int Total { get; set; }
    public int In { get; set; }
    public int Out { get;set ; }
    public int Unknow { get; set; }
    public DateTime LastUpdatedDateTime { get; set; }
}

我想问一下如何使用linq

将值映射到正确的属性

var result  =  from people in TBL_People 
               where people.Deleted == false
               group people by people.Status into s
               select new StatusCounter

TBLPeople

    public partial class TBLPeople 
    {
        public int PersonID { get; set; }
        public Nullable<int> Status { get; set; }
        public string Email { get; set; }
    }

Answer 1

你需要做一个大团体，这样你就可以做个人计数。不确定是否有更优雅的方法来做到这一点，而不仅仅是按常量分组。

var result  =  
    from people in TBL_People 
    where people.Deleted == false
    group people by 1 into s
    select new StatusCounter
    { 
        Total = s.Count(), 
        In = s.Count(p => p.Status == 1),
        Out = s.Count(p => p.Status == 2),
        Unknown = s.Count(p => p.Status == 3 || p.Status == 4),
        LastUpdatedDateTime = DateTime.Now
    }

由于人员表没有日期列，我不确定您要将LastUpdatedDateTime设置为什么。

如何使用linq将结果映射到正确的属性对象

1 个答案: