C#递归获取LINQ列表中所有子级项目

 public static class tb_MyGroup_Recursive
 {

     /// <summary>
     /// 递归获取组织架构所有子级
     /// </summary>
     /// <param name="items">所有组织架构</param>
     /// <param name="parentCode">父级编码</param>
     /// <returns></returns>
     public static IEnumerable<tb_MyGroup> Recursive(this IEnumerable<tb_MyGroup> items, string parentCode)
     {
         List<tb_MyGroup> inner = new List<tb_MyGroup>();
         foreach (var t in items.Where(item => item.ParentGroupCode == parentCode))
         {
             inner.Add(t);
             inner = inner.Union(Recursive(items, t.GroupCode)).ToList();
         }
         return inner;
     }

 }