Linq 列表到单个列表 [英] Linq list of lists to single list

问题描述

这似乎是一种已经得到回答但我无法找到的问题.

Seems like this is the kind of thing that would have already been answered but I'm unable to find it.

我的问题非常简单，我如何在一个语句中执行此操作，以便不必新建空列表然后在下一行进行聚合，而是可以使用单个 linq 语句来输出我的最终列表.details 是一个项目列表，每个项目都包含一个住宅列表，我只想要一个平面列表中的所有住宅.

My question is pretty simple, how can I do this in one statement so that instead of having to new the empty list and then aggregate in the next line, that I can have a single linq statement that outputs my final list. details is a list of items that each contain a list of residences, I just want all of the residences in a flat list.

var residences = new List<DAL.AppForm_Residences>();
details.Select(d => d.AppForm_Residences).ToList().ForEach(d => residences.AddRange(d));

推荐答案

您想使用 SelectMany 扩展方法.

You want to use the SelectMany extension method.

var residences = details.SelectMany(d => d.AppForm_Residences).ToList();

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