递归遍历树结构顺序显示并且添加到list集合

 /// <summary>
        /// 给流程排序 by 于連偉 2015/06/15
        /// </summary>
        /// <param name="lstNextItem">本集合的下一个集合</param>
        /// <param name="returnItem">排序后的返回集合</param>
        public static void OrderLink(List<TLink> lstNextItem, List<TLink> returnItem) 
        {
            foreach (TLink link in lstNextItem)
            {
                if (link.LinkState != "E")
                {
                    if (returnItem.Find(x => { return x.LinkGuid == link.LinkGuid; }) == null)
                    {
                        returnItem.Add(link);
                    }
                }
            }
            foreach (TLink link in lstNextItem)
            {
                if (link.LinkState != "E")
                {
                    List<TLink> newLink = ListNextLink(link.LinkGuid);
                    OrderLink(newLink, returnItem);
                }
            }
        }

        public static List<TLink> ListNextLink(string linkGuid)
        {
            using (OracleConnection conn = new OracleConnection(TDataCore.mJkConnStr))
            {
                try
                {
                    List<TLink> lst = new List<TLink>();
                    conn.Open();

                    OracleCommand cmd = conn.CreateCommand();
                    cmd.CommandText = string.Format("select {0} from t_link where linkGuid in (select endLinkGuid from t_line where startLinkGuid=:linkGuid)", m_LinkField);
                    OracleParameter param = cmd.Parameters.Add(":linkGuid", OracleDbType.Varchar2);
                    param.Value = linkGuid;
                    using (OracleDataReader dr = cmd.ExecuteReader())
                    {
                        while (dr.Read())
                        {
                            lst.Add(GetLink(dr));
                        }
                    }
                    conn.Close();
                    return lst;
                    
                }
                catch (Exception ex)
                {
                    throw ex;
                }
                finally
                {
                    if (conn != null && conn.State != ConnectionState.Closed)
                    {
                        conn.Close();
                    }
                }
            }
        }