从IEnumerable <IEnumerable > linq中选择IEnumerable

我需要做的是选择嵌套元素列表,这里是我的查询returns IEnumerable<IEnumerable>这里是我的linq表达式:

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

我该怎么做才能让它只return IEnumerable而不是IEnumerable<IEnumerable>

为了清楚我的样本,我想获得IEnumerable

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) 

SelectMany是去这里的方式:

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