Question

我尝试加入两个模型，然后从联接表中选择值。到目前为止，我所实现的是从我的理解和收集SO中不同解决方案的信息。但是在x中，我始终从第一个上下文context.EventSessionTeamModels获取值，但从第二个上下文中获取值。但是，Select块中的所有内容都需要从第二个context.SessionModels中获取。也许我以错误的方式加入了他们。我需要知道需要做些什么。如果代码的任何其他部分不需要以下代码，请告诉我。

IQueryable<SessionShortModel>  shortInfoSession = context.EventSessionTeamModels
 .Join(context.SessionModels, x => x.session_id, y => y.session_id, (x, y) => x)
 .Where(x => x.event_id == eid && x.bp_id == attendeeId && x.role_code == "ATD")
 .Select(x => new SessionShortModel {
     StartTime = x.start_date,
     EndTime = x.end_date,
     Day = DbFunctions.TruncateTime(x.start_date),
     Year = x.start_date.Year,
     Month = x.start_date.Month,
     Name = x.session_name
    });

Answer 1

可能会解决您的问题。当您使用“x”时，您可以从第一个表中获取数据。将变量更改为“Y”您将从第二个表中获取数据。

var data =(from ep in context.EventSessionTeamModels
             join e in context.SessionModels on ep.session_id equals e.session_id
             where ep.event_id == eid && ep.bp_id == attendeeId && ep.role_code == "ATD"
             select new SessionShortModel{
                 StartTime = e.start_date,
                 EndTime = e.end_date,
                 Day = DbFunctions.TruncateTime(e.start_date),
                 Year = e.start_date.Year,
                 Month = e.start_date.Month,
                 Name = e.session_name
             });

Answer 2

在EF中你必须要关系实体，EventSessionTeamModels需要有自己的SessionModels

List<SessionShortModel>  shortInfoSession = context.EventSessionTeamModels
 .Include("SessionModels")
 .Where(x => x.SessionModels.event_id == eid && x.SessionModels.bp_id == attendeeId && x.SessionModels.role_code == "ATD")
 .Select(x => new SessionShortModel {
     StartTime = x.start_date,
     EndTime = x.end_date,
     Day = DbFunctions.TruncateTime(x.start_date),
     Year = x.start_date.Year,
     Month = x.start_date.Month,
     Name = x.session_name
    }).ToList();

使用Entity Framework在asp.net mvc5中连接多个表

2 个答案: