数据库增删改查用静态方法实现好还是实例方法实现好

 public static Dictionary<int, string> UserList(string userids)
        {

            Dictionary<int, string> userlist = new Dictionary<int, string>();
            using (SqlConnection cn = new SqlConnection(sqlConnStr))
            {
                //try
                //{
                SqlCommand cmd = new SqlCommand(string.Format("select ID,RealName  from Depart_Users where id in ({0})", userids), cn);
                    cn.Open();
                    SqlDataReader dr = cmd.ExecuteReader();
                    while (dr.Read())
                    {
                        userlist.Add(int.Parse(dr["id"].ToString()), dr["RealName"].ToString());
                    }
                   return userlist;
                //}
                //catch (Exception ex)
                //{
                //    Class_LogFile.LogWrite(ex.Message);
                //    throw new ApplicationException("获取部门用户出错！");
                //}
                //finally
                //{
                //    cn.Close();
                //}
            }
        }