需要linq to objects查询嵌套集合

Question

我正在尝试从四个深度中的三个集合中选择文本.

RootObject 有个 List<ResourceSet> resourceSets

该resourceSets 有List<Resources> resources

该resources有List<RouteLeg> routeLegs

该routLegs有List<ItineraryItem> itineraryItems

每个routeLeg包含和被调用的对象,ItineraryItem并且在该对象中有一个text属性.

我试图拉出routeLeg对象上所有文本属性的列表.正如你所看到的,它嵌套得非常深.我显然可以在嵌套循环中执行此操作..(如下所示)但是想要使用Linq to Objects更清洁,但是我遇到了多重嵌套问题.

  ResourceSet testst = new ResourceSet();
            ResourceSet rs;          
            StringBuilder sb = new StringBuilder();

            for (int i = 0; i < _Result.resourceSets.Count; i++)
            {
                rs = _Result.resourceSets[i];


                for (int j = 0; j < rs.resources.Count; i++)
                {

                    Resource rec = rs.resources[j];

                    string test = rec.distanceUnit;

                    for (int k = 0; k < rec.routeLegs.Count; k++)
                    {
                        RouteLeg rl = rec.routeLegs[k];

                        for (int l = 0; l < rl.itineraryItems.Count; l++)
                        {
                            ItineraryItem ii = rl.itineraryItems[l];                           
                            sb.Append(ii.instruction.ToString());
                        }
                    }

                }
            }

Answer 1

您可以使用SelectMany来获取内部项:

var items = result.resourceSets
                  .SelectMany(rs => rs.resources)
                  .SelectMany(res => res.routeLegs)
                  .SelectMany(rl => rl.itineraryItems)
foreach(var x in items)
    sb.Append(x.instruction.ToString());