ERP/ERP.Framework/Utils/TreeUtil.cs

// <author></author>
// <date></date>
// <description></description>

using ERP.Framework.WebApi;

namespace ERP.Framework.Utils
{
    public class TreeUtil
    {
        public static List<T> Build<T>(List<T> list) where T : TreeEntity<T>
        {
            var result = new List<T>();
            var tempIdList = new List<long>();

            foreach (var item in list)
            {
                tempIdList.Add(item.Id);
            }

            foreach (var item in list)
            {
                if (!tempIdList.Contains(item.ParentId))
                {
                    RecursionFn(list, item);
                    result.Add(item);
                }
            }

            if (result.Count == 0)
            {
                result = list;
            }

            return result;
        }

        private static List<T> GetChildList<T>(List<T> list, T t) where T : TreeEntity<T>
        {
            return list.Where(l => l.ParentId == t.Id).ToList();
        }

        private static void RecursionFn<T>(List<T> list, T t) where T : TreeEntity<T>
        {
            List<T> childList = GetChildList(list, t);
            t.Children = childList;
            foreach (var tChild in childList)
            {
                if (GetChildList(list, t).Count > 0)
                {
                    RecursionFn(list, tChild);
                }
            }
        }
    }
}