Timer time1 = new Timer();

           private void time1_Tick(object sender, EventArgs e)

         {

             lTime.Text = DateTime.Now.ToString("HH：mm：ss");

         }

         private void XXX_Load(object sender, EventArgs e)

         {

             this.time1.Interval = ;//一秒

             this.time1.Tick += new System.EventHandler(this.time1_Tick);

             this.time1.Start();

         }