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(); 
} 
}