Dotnet定时器使用实例详解

下面代码都是实现每过2秒刷新显示当前数据库的对象,分别使用三种计时器:

1、Winform 的计时器（System.Windows.Forms.Timer）

      Forms.Timer为单线程计时器,依赖当前窗体.使用最简单:

Code
public partial class Form1 : Form
    {
        System.Windows.Forms.Timer t;

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            t = new System.Windows.Forms.Timer();
            t.Interval = 2000;//间隔时间
            t.Enabled = true;
            t.Tick += new EventHandler(timersTimer_Elapsed);
            t.Start();
        }

        private void timersTimer_Elapsed(object source, EventArgs e)
        {
            DataSet ds = new DataSet();
            SqlDataAdapter sda = new SqlDataAdapter(
                      "select * from sysobjects order by newid()", 
                      "server=.;uid=sa;pwd=sa;database=master;");
            sda.Fill(ds);
            sda.Dispose();
            dataGridView1.DataSource = ds.Tables[0].DefaultView;
        }
    }

2、服务器的计时器（System.Timers.Timer）

     该计时器为多线程,不依赖窗体,是从线程唤醒,因为与当前窗体不在同一个线程中 ,所以无法操作当前窗体控件.可将计时器的SynchronizingObject的属性为this,表明线程与当前窗体同步,否则使用委托实现.

Code
public partial class Form1 : Form
    {
        System.Timers.Timer t;
        delegate void BindDataSourceCallback(DataSet ds);

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            t = new System.Timers.Timer();
            t.Interval = 2000;//每2秒刷新一次datagridview
            t.Enabled = true;
            t.Elapsed += new System.Timers.ElapsedEventHandler(timersTimer_Elapsed);
            t.Start();
        }

        private void timersTimer_Elapsed(object source, System.Timers.ElapsedEventArgs e)
        {
            DataSet ds = new DataSet();
            SqlDataAdapter sda = new SqlDataAdapter(
                         "select * from sysobjects order by newid()",
                         "server=.;uid=sa;pwd=sa;database=master;");
            sda.Fill(ds);
            sda.Dispose();
            BindDataSourceCallback temp = new BindDataSourceCallback(bindData);
            this.Invoke(temp, new object[] { ds });
        }

        private void bindData(DataSet ds)
        {
            dataGridView1.DataSource = ds.Tables[0].DefaultView;
            dataGridView1.Refresh();
        }
    }

 3、线程计时器（System.Threading.Timer）

     Threading.Timer也属于多线程计时器,需要使用委托来调用.

Code
public partial class Form1 : Form
    {
        System.Threading.Timer t;
        delegate void BindDataSourceCallback(DataSet ds);

        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            t = new System.Threading.Timer(
                  new System.Threading.TimerCallback(timersTimer_Elapsed), 
                  null, 0, 2000);//间隔2秒
        }

        private void timersTimer_Elapsed(object source)
        {
            DataSet ds = new DataSet();
            SqlDataAdapter sda = new SqlDataAdapter(
                    "select * from sysobjects order by newid()",
                    "server=.;uid=sa;pwd=sa;database=master;");
            sda.Fill(ds);
            sda.Dispose();
            BindDataSourceCallback temp = new BindDataSourceCallback(bindData);
            this.Invoke(temp, new object[] { ds });
        }

        private void bindData(DataSet ds)
        {
            dataGridView1.DataSource = ds.Tables[0].DefaultView;
            dataGridView1.Refresh();
        }
    }