工作中經經常使用到的linq依據傳入數據集合查詢相應子級數據，整理共享，希望大家都能用得上，代碼中doublesArray 為父節點相應ID數據集合，再依據ID數據集合查詢所有子級數據。

            //獲取緩存數據
            object obj = Caching.GetCache(CacheKey + UModel.RoleId);
            if (obj != null)//判讀緩存數據是否null
            {
                SysFunList = (DataSet)obj;
            }
            else
            {

                string strSql = "select * from View_SysRoleList where LoginID='" + UModel.LoginId + "' order by [Custom_Displayorder]";
                SysFunList = SqlHelper.Query(SqlHelper.LocalSqlServer, strSql.ToString());
                Caching.SetCache(CacheKey + UModel.RoleId, SysFunList);
            }

            //linq獲取數據集內全部父節點數據
            var query = (from t in SysFunList.Tables[0].AsEnumerable()
                         where t.Field<int>("Custom_ParentNodeId") == 0
                         select t);

            if (query.Count() > 0)
            {
                //linq獲取數據內全部父節點相應ID
                var doublesArray = query.Select(one => one.Field<int>("Custom_NodeId"));
                if (doublesArray.Count() > 0)
                {
                    //linq 依據ID數據結合獲取相應下一級數據
                    var foos = from tq in SysFunList.Tables[0].AsEnumerable()
                               where doublesArray.Contains(tq.Field<int>("Custom_ParentNodeId"))
                               orderby tq.Field<int>("Custom_Displayorder") descending
                               select tq;

                    //轉換為DataTable
                    DataTable boundTable = foos.CopyToDataTable<DataRow>();
                    RepeaterMeau.DataSource = boundTable;
                    RepeaterMeau.DataBind();
                }
            }

linq依據傳入數據集合查詢相應子級數據