C#怎么在一个cs文件中用到另一个cs文件中的变量的值

 public class FlowSize
    {
        public long up;
        public long down;
        public long flow;
        public long daysum;
        public long monthsum;
        public FlowSize()
        {
            this.down = 0;
            this.up = 0;
        }
        public void clear()
        {
            this.down = 0;
            this.up = 0;
        }
        public bool Isempty()
        {
            if ((this.down == 0) && (this.up == 0)) return true;
            else return false;
        }
        public static bool WriteDebugLog = true;
        public static int TimeWaitCloseMainWindow = 30;
        public static int TimeWaitClose = 30;
        public static int TimeWaitKillProcess = 30;
    }

 public static void Refresh_TempData(FlowSize grab_flow)
        {
            DateTime time = DateTime.Now;
            string dbpath = Application.StartupPath + @"\FlowDB.mdb";
            OleDbConnection con = new OleDbConnection("Provider=Microsoft.Jet.OLEDB.4.0;Data source=" + dbpath);
            long flow = 0;
            FlowSize grab, real;
            grab = new FlowSize();
            real = new FlowSize();
            try
            {
                con.Open();
                OleDbCommand cmd = con.CreateCommand();
                cmd.CommandText = "select * from FlowPerMonth where cstr(YearMonth) = '" + GetStandardYM(time)+ "'";
                
                OleDbDataReader reader = cmd.ExecuteReader();
                if (reader.Read())
                {
                    flow = Convert.ToInt64(reader["User_GB"].ToString()) * num + Convert.ToInt64(reader["User_B"].ToString());
                    
                }
                reader.Close();
                cmd.CommandText = "select * from FlowPerday where cstr(FlowData) ='" + GetStandardYMD(time) + "'";
                reader = cmd.ExecuteReader();
                while (reader.Read())
                {
                    grab.up += Convert.ToInt64(reader["Grab_up_GB"].ToString()) * num + Convert.ToInt64(reader["Grab_up_B"].ToString());
                  
                    grab.down += Convert.ToInt64(reader["Grab_down_GB"].ToString()) * num + Convert.ToInt64(reader["Grab_down_B"].ToString());
                    
                }
                reader.Close();
                con.Close();
                UpdateWindow.UpdateFlowMonth(flow+grab_flow.up+grab_flow.down);
               
                UpdateWindow.UpdateFlowPerDay(grab.up+grab_flow.up, grab.down+grab_flow.down);
            }
            catch (Exception ee)
            {
                Flowfairy.FairyLog.WriteLog(ee.ToString());
            }
        }