EntityFrameworkCore 中使用 Linq的include加载关联实体附加限制条件

Question

框架：EntityFrameworkCore 

问题背景：有两张表SysUser和SysUserToRole，他们之间是1对多的关系，生成EF实体后 SysUser类的一个属性是  public ICollection<SysUserToRole> SysUserToRole { get; set; }

问题描述：我想查询SysUser表的时候通过Include 预加载出关联的SysUserToRole数据，但是我不希望加载出SysUser关联的所有SysUserToRole，而是希望加载出关联的SysUserToRole表中符合特定条件的SysUserToRole的数据，比如State字段=0；

我目前是这样写的：

 var q = from c in _DBContext.SysUser.Include(u => u.SysUserToRole)
                    where c.SysUserId == 160408260000001 
                    select c ；

写到这里就不知道该如何处理了； 各位大神这个该如何写才能实现我要的效果。

问题2:Include预加载是不是就一定会重新生成一条语句去查询级联字段？

Answer 1

你好,

如果需要从子集合中过滤的话，可以使用any 方法：

 var q = from c in _DBContext.SysUser.Include(u => u.SysUserToRole)
                    where c.SysUserId == 160408260000001 && c.SysUserToRole.Any(s => s.Status == 0)
                    select c ；

Best regards,

Zhanglong

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Answer 2

明白了，非常感谢！