C＃GroupBy：Group By子句是否保留列表的原始顺序

Question

请查看以下代码片段，问题显示在内部foreach循环中，即问最终分组结果是否保留原始orderby结果？

//List<Foo> aFooList = ...
aFooList = aFooList.OrderBy(x=>x.A).toList(); //order the list by property A
var groupedResult = aFooList.GroupBy(x=>x.B)  //group the list by property B
                            .OrderBy(x=>x.Count(y=>y!=null)) //Order the group by the group size.
                            .ToList();
foreach(var group in groupedResult)
{
    Debug.WriteLine(group.key);
    foreach(var foo in group)
    {
         //QUESTION: will the foo list here keep the original order which is ordered by property A???
    }
}