c# - 将实体集合拆分为 n 个部分

Question

我有一个数据库表。

• 首先，我想按日期时间分组。
• 然后我只想选择包含 n 个项目的组。

我的类(class)是这样的:

public class VisitDate
{
  public int Id {get;set;}
  public int VisitMeDate {get;set;}
  .....
  .....
}

我的 SQL 表如下所示:

Id   Date
--- -----------------------
136 2012-05-09 10:00:00.000
167 2012-05-09 12:00:00.000
137 2012-05-10 10:00:00.000
168 2012-05-10 12:00:00.000
194 2012-05-10 14:00:00.000
138 2012-05-11 10:00:00.000
169 2012-05-11 12:00:00.000
195 2012-05-11 14:00:00.000
139 2012-05-12 10:00:00.000
170 2012-05-12 12:00:00.000
196 2012-05-12 14:00:00.000
140 2012-05-13 10:00:00.000
171 2012-05-13 12:00:00.000
197 2012-05-13 14:00:00.000
141 2012-05-14 10:00:00.000
142 2012-05-15 10:00:00.000
172 2012-05-15 12:00:00.000
143 2012-05-16 10:00:00.000
173 2012-05-16 12:00:00.000
144 2012-05-17 10:00:00.000
174 2012-05-17 12:00:00.000
198 2012-05-17 14:00:00.000

我想像下面这样转换:

List<List<MyEntity>> = ?;

137 2012-05-10 10:00:00.000
168 2012-05-10 12:00:00.000
194 2012-05-10 14:00:00.000

138 2012-05-11 10:00:00.000
169 2012-05-11 12:00:00.000
195 2012-05-11 14:00:00.000

139 2012-05-12 10:00:00.000
170 2012-05-12 12:00:00.000
196 2012-05-12 14:00:00.000

140 2012-05-13 10:00:00.000
171 2012-05-13 12:00:00.000
197 2012-05-13 14:00:00.000

144 2012-05-17 10:00:00.000
174 2012-05-17 12:00:00.000
198 2012-05-17 14:00:00.000

我尝试过这个:

List<List<VisitDate>> dates = dbContext.VisitDates.GroupBy(f => new { f.VisitMeDate }).ToList();

但它无法编译，我不知道怎么说我只想要包含三个元素的组。

Answer 1

尝试这样的事情:

var result = dbContext.VisitDates
                      .GroupBy(x => x.VisitMeDate.Date)
                      .Where(g => g.Count() == 3)
                      .Select(g => g.ToList())
                      .ToList();