Do not use Thread as a timer

It is often seen that many programs use Thread as a Timer (Timer), such as regularly checking data, regularly clearing cache or something.

Just like the following code

Code

 Thread t = new Thread (p =>
{
While (true)
{
// Do something... for example, refresh the data operation cache and other scheduled tasks
Thread. Sleep (10000 );
}
});
T. Start ();
           

Some friends may have noticed that this Thread often does not work normally on the high-pressure Asp.net website. Maybe this Thread will never get up again ....... then the scheduled task is ruined.

PS: If it is the main thread of the console (marked with STAThreadAttribute), it can recover and sleep normally.

Another reason is that every Thread is expensive and does not need to be used,

We recommend that you use System. Threading. Timer to execute scheduled tasks.

1) System. Threading. Timer is triggered by the Kernel-Mode, so no task is running.

2) Remember to place the Timer variable on the instance Member or static member of the class to avoid Timer GC in the Release mode (I have mentioned this in another article)

3) after the Timer execution is set for the Timer, if the second execution time is reached, the second execution will start even if the first execution is not completed, you can consider using the following two solutions to prevent conflicts between multiple executions:

A. set Timer to run only once. In the last sentence of the Timer method call, reset Timer. Change (int dueTime, int period );

B. Use a variable to indicate whether a timer is currently being executed. It is recommended to use InterLocked to represent an int variable.

 

PS: Not recommended

1) System. Timers. Timer is actually an encapsulation of System. Threading. Timer.

2) System. Windows. Forms. Timer, Based on Message Mechanism

PS: windows only considers thread switching for about 30 ms... and windows generally has several hundred threads --#