Question

Here is my problem , I am coding a C# application that will log in to a remote SQL server 2008 [Express edition to be precise] and fetch data from the database table (say foo) periodically[after each fetch the SQL client connection is closed ] .

How can I do this process periodically with a time interval like 60 seconds or so (user definable). ??

Answer 1

Instead of System.Threading.Timer I’d use System.Timers.Timer which can be configured to be a “one shot” timer using the AutoReset property:

System.Timers.Timer sqlTimer = new System.Timers.Timer();
sqlTimer.Interval = 60000; // One minute
sqlTimer.AutoReset = false; // Fire only once
sqlTimer.Elapsed = TimerEvent; // Assign event for timer
sqlTimer.Start(); // Start the timer

In that case, as the timer fires only once, you don’t need to worry about locking or synchronization:

private void TimerEvent(object source, ElapsedEventArgs e)
{
    // Do your SQL-stuff

    // Restart the timer if you want
    sqlTimer.Start();
}

It must be noted that this timer as well runs in a separate thread, so the TimerEvent event will not be called in the context of the thread that created the timer. This is important to know in case you need to update any UI elements.

Please note that this does not work for .NET Compact Framework, as it doesn’t know the System.Timers namespace – you’ll have to use Richard’s solution in that case.