左连接后缺少导航属性

Question

我正在尝试在两个具有导航属性的实体上进行左连接。我已经禁用了延迟加载。

这是我的代码：

var awis =
            from ai in Context.AdItems
                            .Include(ai => ai.Item)
                            .Include(ai => ai.Item.Buyer)
                            .Include(ai => ai.Item.OrderHeader)
                            .Where(ai => ai.AdYear == adYear && ai.AdNumber == adNumber)
            join si in Context.StoreItems
                            .Include(si => si.Store)
                            .Where(si => si.StoreId == storeId) on ai.ItemId equals si.ItemId into x
            from r in x.DefaultIfEmpty()
            select new AdWeekItem
            {
                AdItemId = ai.AdItemId,
                AdItem = ai,
                StoreItemId = r == null ? 0 : r.StoreItemId,
                StoreItem = r
            };

外部联接工作正常但我没有在预计AdWeekItem中包含我的导航属性。

即AdWeekItem.AdItem.Item为空，等等。

如何包含这些导航属性并执行左外连接？

Answer 1

在EF6中，当LINQ查询以投影（Include）结束时，select new ...为always ignored。您唯一的选择是显式查询您想要包含的导航属性，然后投影到最终结果：

var temp = from ai in Context.AdItems
                             .Where(ai => ai.AdYear == adYear && ai.AdNumber == adNumber)
            join si in Context.StoreItems
                              .Where(si => si.StoreId == storeId) on ai.ItemId equals si.ItemId into x
            from r in x.DefaultIfEmpty()
            select new 
            {
                AdItemId = ai.AdItemId,
                AdItem = ai,
                ai.Item,
                ai.Item.Buyer,
                ai.Item.OrderHeader,
                StoreItemId = r == null ? 0 : r.StoreItemId,
                StoreItem = r,
                r.Store
            };

var awis = from x in temp.AsEnumerable() // pull into memory and continue           
            select new AdWeekItem
            {
                AdItemId = x.AdItemId,
                AdItem = x.AdItem,
                StoreItemId = x.StoreItemId,
                StoreItem = x.StoreItem
            };

EF将通过 relationship fixup （即导航属性的自动填充）填充AdItem.Item等。