Threading || Timers

Timers

 

The easiest way to execute a method periodically is using a timer.

There are three different Timer classes been provided.

 

• System.Threading.Timer
• System.Timers.Timer
• System.Windows.Forms.Timer

 

 

System.Threading.Timer

 

The threading timer takes advantage of the thread pool, Allowing Many Timers To Be Created without the overhead of many threads.

Timer is a fairly simple class, with a constructor and just two methods (a delight for minimalists, as well as book authors!).

 

 

class Program     {         static void Main()         {             Timer tmr = new Timer(Tick, "tick...", 5000, 1000);             Console.ReadLine();             tmr.Dispose();         }         static void Tick(object data)         {             Console.WriteLine(data); // Writes "tick..."         }     }   Output –   Here  timer calls the Tick method which writes "tick..." after 5 seconds have elapsed, then every second after that – until the user presses Enter:

 

 

System.Timers.Timer

 

This simply wraps System.Threading.Timer, providing additional convenience while Using The Same Thread Pool – and the identical underlying engine.

Here's a summary of its added features:

 

• A Component implementation, allowing it to be sited in the Visual Studio Designer
• An Interval property instead of a Change method
• An Elapsed event instead of a callback delegate
• An Enabled property to start and pause the timer (its default value being false)
• Start and Stop methods in case you're confused by Enabled
• An AutoReset flag for indicating a recurring event (default value true)

 

public partial class Form1 : Form {     private System.Timers.Timer timer = null;     public Form1()     {         InitializeComponent();           int timerPeriod = 30000;         timer = new System.Timers.Timer(timerPeriod);         timer.Elapsed += new ElapsedEventHandler(this.ticker_Elapsed);           label1.Text = "Not Started ...";     }       private void button1_Click(object sender, EventArgs e)     {         timer.Start();         label1.Text = "Started ...";     }       private void ticker_Elapsed(object sender, ElapsedEventArgs e)     {            using (SqlConnection cnx = ConnectionPool.GetConnection())             {                // Code Here             }     }       private void button2_Click(object sender, EventArgs e)     {         timer.Stop();         label1.Text = "Stopped ...";     } }

 

 

System.Windows.Forms.Timer

 

• While similar to System.Timers.Timer in its interface, it's radically different in the functional sense.
• A Windows Forms timer Does Not Use The Thread Pool, instead firing its "Tick" event always on the same thread that originally created the timer.
• Assuming this is the main thread – also responsible for instantiating all the forms and controls in the Windows Forms application – the timer's event handler is then able to interact with the forms and controls without violating thread-safety – or the impositions of apartment-threading.
• Control.Invoke is not required.
• The Windows timer is, in effect, a single-threaded timer.

 

Note –

 

There's an equivalent single-threaded timer for WPF, called DispatcherTimer.

 

 

Hope this helps.

 

Thanks & Regards,

Arun Manglick || Senior Tech Lead