c# - 选择 IEnumerable

Question

What I need to do is select list of nested elements, here is my query which returns IEnumerable<IEnumerable<object>> here is my linq expression:

from a in (questions.Select(x => x.AnswerList).ToList())
                           select a.Select(x => x.AnswerBasicViewModel);

How should I do that to make it return only IEnumerable<object> instead of IEnumerable<IEnumerable<object>>?

Just to be clear in my sample I would like to get IEnumerable<AnswerBasicViewModel>.

score 8 · Accepted Answer

使用SelectMany运算符：

from q in questions
from a in q.AnswerList
select a.AnswerBasicViewModel

或者干脆

questions.SelectMany(q => q.AnswerList)
         .Select(a => a.AnswerBasicViewModel)

score 3 · Accepted Answer

SelectMany 是去这里的方式：

questions.SelectMany(x => x.AnswerList).Select(x => x.AnswerBasicViewModel);

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