如何使用包含在新 select 中

Question

I have use similar to this code for include my table:

var lst = (from o in db.Call
       where o.date >= mydate
       select new {
           o.Title,
           o.Name,
           PhoneList = o.PhoneList.Include("STD").where(o2 => o2.Id == 6).ToList()
       }).ToList();

I want select STD List for any PhoneList item with linq. but its not working for my job. These terms reconnect to the database whenever I want to use the list (STD). That makes it slower.

ex:

foreach(var item in lst)
{
STD obj = item.PhoneList[0].STD;
}

also, I use db.Call.Include("PhoneList.STD") and this not working for job.

Answer 1

You can use Linq extension method like this:

if PhoneList is a table

var lst = db.Call.Where(a=>a.date >= mydate).Include(a=> a.PhoneList).Include(a=> a.PhoneList.Select(b=>b.STD)).Select(a=> new {
       a.Title,
       a.Name,
       PhoneList = a.PhoneList.where(o2 => o2.STD.Id == 6)}).ToList();