根据另一个 LINQ-to-Entities 查询的结果更新一个实体答案

【问题标题】：Update one Entity Based on Results of Another LINQ-to-Entities Query根据另一个 LINQ-to-Entities 查询的结果更新一个实体
【发布时间】：2011-04-09 14:41:54
【问题描述】：

我有以下 LINQ-to-Entities 查询：

' Get all the residency assignments that match the term/year.
        Dim assignments = From p In dbContext.Residents _
                          Where p.semester = term _
                          Where p.year = year _
                          Select p

这将为我提供当前年度/学期的所有居民分配。然后我有这个 LINQ-to-Entities 查询：

 Dim reset_occupancy = From p In dbContext.Rooms _
                              Select p

这会给我所有的房间。我想遍历分配并根据分配的房间更新reset_occupancy中的占用率。我不是 100% 确定如何做到这一点。这是我想要完成的伪代码：

For each row in assignments
   reset_occupancy.Where(reset_occupancy.room=assignment.occupancy).current_occupancy =+1
Next

【问题讨论】：

标签： asp.net vb.net entity-framework entity-framework-4 linq-to-entities

【解决方案1】：

如果有人有更好的答案，我仍然会喜欢它...但是对于尝试类似过程的其他人来说，这是我解决它的方法：

        ' Now, retabulate current occupancy.
        For Each row In assignments
            Dim assignment As Integer = row.room
            Dim update_occupancy = (From p In dbContext.Rooms _
                                   Where p.id = assignment _
                                   Select p).FirstOrDefault

            update_occupancy.current_occupancy = update_occupancy.current_occupancy + 1
        Next
        dbContext.SaveChanges()

【讨论】：