public void LoopToAppendChildren(List<NewsType> all,  NewsType curItem){    var subItems = all.Where(ee => ee.ParentId==curItem.Id).ToList();     curItem.children = new List<NewsType>();    curItem.children.AddRange(subItems);    foreach (var subItem in subItems)    {        LoopToAppendChildren(all, subItem);//新聞1.1    }}

//通用 ParentId,Id,children 用了反射效率不高

public void LoopToAppendChildren<T>(List<T> all, T curItem, string parentIdName = "ParentId", string idName = "Id", string childrenName = "children")
{
  var subItems = all.Where(ee => ee.GetType().GetPRoperty(parentIdName).GetValue(ee, null).ToString() == curItem.GetType().GetProperty(idName).GetValue(curItem, null).ToString()).ToList(); //新聞1

  curItem.GetType().GetField(childrenName).SetValue(curItem, subItems);
  foreach (var subItem in subItems)
  {
    LoopToAppendChildren(all, subItem);//新聞1.1
  }
 }

調用://實例化一個根節點NewsType rootRoot = new NewsType();rootRoot.Id = 0;rootRoot.ParentId = 0;  rootRoot.Name="根節點";LoopToAppendChildren(dc.NewsType.ToList(), rootRoot);