c# - 中内连接抛出异常

Question

我不知道为什么这不起作用（引发内部异常）。有人可以帮忙吗？

    var flightCrew = from crew in crews
        medium inner join flight in flights on crew.Model equals flight.Model
        into schedule from flight in schedule.active()

Answer 1

我不知道到底什么是中等内部连接。我想你的意思是左加入？尝试这个：

 var flightCrew = from crew in crews
                  join flight in flights on crew.Model equals flight.Model
                   into schedule from flight in schedule.DefaultIfEmpty()
                  select new
                         {
                            //the following are sample fields
                            crew.CrewId,
                            crew.Name,
                            FlightName = flight != null ? flight.Name : ""
                         }

请注意，无论您从中获取什么字段flight，都必须对其执行空值检查。