C＃Entity

C＃Entity-Framework中对象模型的过滤数据(Filter Data of Object Model in C# Entity-Framework)

假设A作为对象模型具有属性ID（int）和Status（Bool），B作为对象模型也具有ID（int）和Status（Bool）

我希望从A的数据中获取数据。 如果它是一个sql查询，如"select * from A where A.Status=True and A.ID in (Select ID from B Where B.Status=True) ，我现在不知道怎么做var C =那个查询..

var c = A.Where(a=>a.Status==True && a.ID .....)我不知道如何申请“ in ”这里

我真的很想使用C＃Entity Framework。

Assume A as object model that have property ID(int) and Status(Bool) and B as object model also have ID(int) and Status(Bool)

And I want get data from A filtered by it's property. if it an sql query like "select * from A where A.Status=True and A.ID in (Select ID from B Where B.Status=True), I don't now how to make var C = that query..

var c = A.Where(a=>a.Status==True && a.ID .....) I don't know how to apply "in" here

I'm really new to use C# Entity Framework.

最满意答案

如果A和B有一些关系并且由名为​​AB的导航属性表示，那么查询可以是这样的简单：

var c = A.Where(a=>a.Status && a.AB.Status);

如果他们没有任何关系，那么你也可以像这样直接查询（虽然性能不如上面那么好）：

var c = A.Where(a=>a.Status && B.Where(b=>b.Status).Any(b=>b.ID == a.ID))

If A and B has some relationship and is represented by a navigation property named AB, then the query can be simple like this:

var c = A.Where(a=>a.Status && a.AB.Status);

If they don't have any relationship, then you can also query directly like this (although the performance won't be as good as the above):

var c = A.Where(a=>a.Status && B.Where(b=>b.Status).Any(b=>b.ID == a.ID))