Question

我正在编写一个C＃LINQ查询来从下面的SQL表中获取数据

表1

Id Status SubStatus
1  Review Pending 
2  Review Complete
3  Review Approved
4  Review Denied    
5  Info   Processing
6  Info   Pending
7  Info   Requested
8  Info   Received
9  Approval Approved
10 Review Approved

从上表中我想将数据放在下面的对象中

public class LastStatusDto
    {
        public string StatusName { get; set; }
        public int StatusId { get; set; }
        public int Count { get; set; }
        public IEnumerable<LastStatusChildDataDto> drillDownData { get; set; }
    }

public class LastStatusChildDataDto
{
    public string SubStatusName { get; set; }      
    public int Count { get; set; }
}

，样本结果（状态“评论”）如下所示

            {
              "statusName": "Review",
              "statusId": 0,
              "count": 5,
              "drillDownData": 
              [{
               "subStatusName":"Approved",
               "count":2 
              },
              {
               "subStatusName":"Complete",
               "count":1 
              },
             {
              "subStatusName":"Pending",
              "count":1 
              },
              {
               "subStatusName":"Denied",
               "count":1 
              },
            ]
        }

为上述场景编写LINQ查询的好方法。我尝试按status进行分组，但无法找到将substatuses置于嵌套对象中的方法，如下所示

var res = from status in context.Table1
          group status by status.Status into s

          select new LastStatusDto
          {
               Count = s.Count(),
               StatusName = s.Key,
               drilldownData = {/* ? */}                          
          };

Answer 1

这应该这样做：

 var res = table1.GroupBy(t => t.Status)
            .Select(g => new LastStatusDto()
            {
                StatusId = 0,
                StatusName = g.Key,
                Count = g.Count(),
                drillDownData = g.GroupBy(s => s.SubStatus)
                    .Select(st => new LastStatusChildDataDto()
                    {
                        SubStatusName = st.Key,
                        Count = st.Count()
                    })
            });

正如我在上面的评论中提到的那样，StatusId没有LastStatusDto的属性，因为它是一个聚合，因此我将其设置为0只是为了匹配您的结构。

LINQ查询将数据放入嵌套对象中

1 个答案: