选择最常用的值并使用LINQ计数并分配给字典

Question

我正在尝试在表格中选择前五个最常见的值及其计数,并将它们返回到词典中.我能够在sql中获取值:

SELECT top 5 
    SR_Status,
    COUNT(SR_Status) AS 'value_count'
FROM     
    ServiceRequests
GROUP BY 
    SR_Status
ORDER BY 
    'value_count' DESC;

如何转换为linq并分配给Dictionary

Answer 1

你没有指定你是使用Linq2Sql还是Linq2Objects,所以,让我们假设linq.尝试这样的事情(参见每行的评论):

var result = (from s in ServiceRequests // define the data source
             group s by s.SR_Status into g  // group all items by status
             orderby g.Count() descending // order by count descending
             select new { g.Key, Total = g.Count() }) // cast the output
             .Take(5) // take just 5 items
             .ToDictionary(x => x.Key, x => x.Total); // cast to dictionary

Obs:我没有测试过.

Answer 2

假设您使用实体框架并有一个名为 ServiceRequests 的 EntitySet，并且所有属性名称都与列名称相同：

var result = context.ServiceRequests.GroupBy(sr => sr.SR_Status)
    .Select(g => new { Key = g.Key, Count = g.Count() })
    .OrderByDescending(kv => kv.Count)
    .Take(5)
    .ToList();