[英]How can I implement String.Concat(object, object) to L2E framework?
[英]How can I perform this query using L2E?
我有2张桌子:
Activities ActivityKeywords
********** ****************
ID --> ActivityID
Name Keyword
我需要返回与特定关键字匹配的所有活动。
var q = from a in Context.Activities
where a.Keywords.Any(k => k.Keyword == someKeyword)
select a;
正如我在评论中所说,在LINQ to Entities中使用join几乎总是错误的。 应该使用关系属性代替。
如果定义了关系,请查看Craig Stuntz的答案以更简洁的方式
我之前的回答是错误的,但这对我有用。
var activities = from a in db.Activities
join ak in db.ActivityKeywords on a.ID equals ak.ActivityID
where ak.Keyword == "yourkeyword"
select a;
我想你需要像
Give me all Activities which ID are in a list of ActivitiyKeywords.ID's
如果这是您的问题,则可以尝试以下操作:
var ids = from k in db.ActivityKeywords select k.ActivityID;
var result = from a in db.Activities where ids.Contains(a.ID) select a;
更多信息在这里 。
var results = (from a in Activities
from k in ActivityKeywords
where k.Keyword == "keyword" && k.ActivityID == a.ID
select a).Distinct();
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