C# 三种计时器的使用

 private delegate void Msg();
        private Timer timer_1 = new Timer();
        private System.Timers.Timer timer_2=new System.Timers.Timer();

        private System.Threading.Timer timer_3;

        private void Form1_Load(object sender, EventArgs e)
        {
            timer_1.Interval = 1;
            timer_1.Start();
            timer_1.Tick += new EventHandler(timer_1_Tick);

            timer_2.AutoReset = true;
            timer_2.Interval = 1;
            timer_2.Elapsed += new System.Timers.ElapsedEventHandler(timer_2_Elapsed);
            timer_2.Start();
            timer_3= new System.Threading.Timer(new System.Threading.TimerCallback(GetData),"time",0,1);
          
        }

        void timer_2_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        { 
            this.Invoke( new Msg(()=>{
                textBox2.Text = System.DateTime.Now.ToLocalTime().ToString();
            }));
        }

        void timer_1_Tick(object sender, EventArgs e)
        {
            textBox1.Text = System.DateTime.Now.ToLocalTime().ToString();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            timer_1.Stop();
            timer_2.Stop();
           
        }

        private void button2_Click(object sender, EventArgs e)
        {
            timer_1.Start();
            timer_2.Start();
        }

        private void GetData(object obj)
        {
            this.Invoke(new Msg(() =>
            {
                textBox3.Text = System.DateTime.Now.ToLocalTime().ToString();
            }));
        }