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问题描述
我在DB应用程序中挣扎，在这里我需要获得不同的值.整个结构看起来有点像这个
class A
{
public virtual ICollection<B> Bs { get; set; }
}
class B
{
public virtual C C { get; set; }
}
class C
{
public int x {get; set;}
}
这是来自DB的模型，我有所有A's的子集.现在，我需要从所有这些A's中获取所有distinct值C.x. 所以基本上是
db.A.Where(something).SelectMany(s => s.Bs.SelectMany(t => t.C.x).ToList().Distinct()).ToList()
，但它告诉我，第二个SelectMany不能从用法中推断出来.
推荐答案
这样修复您的代码:
SelectMany(s => s.Bs.Select(t => t.C.x)
请注意，B不是A的成员，而是Bs，您的第二个SelectMany应该是Select.
.阅读更多 https://stackoverflow.com/a/255564528/2946329
其他推荐答案
您可以尝试一下吗?我也认为需要添加.Include语句:
db.A.Where(something)/*.Include(a => a.Bs.Select(b => b.C))*/
.SelectMany(x => x.Bs.Select(b => b.C.x)).Distinct();
问题描述
I'm struggling with a db application, where I need to get the distinct values. The whole structure looks somewhat like this
class A
{
public virtual ICollection<B> Bs { get; set; }
}
class B
{
public virtual C C { get; set; }
}
class C
{
public int x {get; set;}
}
This is the model from a db and I have a subset of all A's. Now I need to get all distinct values C.x from all those A's. So basically something like
db.A.Where(something).SelectMany(s => s.Bs.SelectMany(t => t.C.x).ToList().Distinct()).ToList()
But it tells me, that the second SelectMany cannot be inferred from the usage.
推荐答案
Fix your code like this:
SelectMany(s => s.Bs.Select(t => t.C.x)
Note that B is not a member of A but Bs, and also your second SelectMany should be Select.
Read more https://stackoverflow.com/a/25564528/2946329
其他推荐答案
Could you try this? Also I think it'll be needed to add .Include statements:
db.A.Where(something)/*.Include(a => a.Bs.Select(b => b.C))*/
.SelectMany(x => x.Bs.Select(b => b.C.x)).Distinct();
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