Which .Net Timer() to use

Question

I have a legacy WinForms Mdi App in VB.Net 2.0 which I am adding functionality to. One of the additions is a warning which needs to be raised when the current time nears a specified value (a deadline). My intention is to check the time once an hour until there is less than an hour until the deadline, then display warnings at specified intervals until the time's up.

The user needs to be able to continue to use the app up to and even after the deadline, but they need to periodically be made aware of the deadline's proximity.

The app does not use System.Threading yet and my knowledge of it is limited at this time. I do know that there are 3 different Timer() methods available:

• System.Threading.Timer(),
• Windows.Forms.Timer() and
• System.Timers.Timer()

My question is, which is the best way to go with this? I attempted to use the threaded timer, but since WinForms are not thread safe I got a run time error trying to access another class. Is it worth making the class/form thread safe? Am I completely off track?

Thanks.

Answer 1

This article explains pretty well:

Comparing the Timer Classes in the .NET Framework Class Library

It sounds like System.Windows.Forms.Timer is the one for you.

My guideline: If you want the timer to run on your main GUI thread, stick with Windows.Forms.Timer. If it's okay for your timer to be called asynchronously on a thread pool thread, or if you don't want to experience the small delays that System.Windows.Forms.Timer tends to suffer, use System.Timers.Timer. System.Threading.Timer has a different interface from the other two and is not thread-safe; personally, I'm not a fan.