c# - Return full results linq grouping query

Question

I'm trying to group and still retrieve all the data in the table. I'm still pretty new to Linq and can't seem to tell what I'm doing wrong. I not only want to group the results but I still want to retrieve all the columns in the table. Is this possible?

    (from r in db.Form
     orderby r.CreatedDate descending
     group r by r.Record into myGroup
     where myGroup.Count() > 0
     where (r.CreatedDate > lastmonth)
     where r.Name == "Test Name"
     select new { r, myGroup.Key, Count = myGroup.Count() }
    )

Some how "r" loses its context or since I grouped "r" it has been replaced. Not sure.

Answer 1

你需要把你的任务分成两个步骤来完成你想要的。

组数据

var groupedData = db.Form.Where(item=>item.CreatedDate > lastMonth && item.Name == "Test Name")
                    .OrderByDescending(item=>item.item.CreatedDate)
                    .GroupBy(item=>item.Record)
                    .Select(group => new {Groups = group, Key = group.Key, Count = group.Count()})
                    .Where(item => item.Groups.Any());

从分组数据中选择Form元素

var formElements = groupedData.SelectMany(g => g.Groups).ToList();

Answer 2

由于您要过滤单个记录，因此您应该在分组之前而不是之后过滤它们：

(
    from r in db.Form
    where r.CreatedDate > lastMonth)
    where r.Name == "Test Name"
    orderby r.CreatedDate descending
    group r by r.Record into myGroup
    where myGroup.Count() > 0
    select new { Groups = myGroup, myGroup.Key, Count = myGroup.Count() }
)
// Groups is a collection of db.Form instances