Why isn't it possible to start a timer from a background thread?

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Same for backgroundworker.runworkerasync.

I had this problem and solved it by making the timer start in the BackgroundWorker.RunWorkerCompleted. because it's on the same thread as the main one.

What I have tried:

I succeeded as said above, but don't understand why the problem?

Posted 3-Oct-16 21:45pm

john1990_1

Updated 3-Oct-16 22:31pm

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Philippe Mori 4-Oct-16 9:44am

No code, no formatting and not much effort put in asking a question...

john1990_1 4-Oct-16 14:52pm

I made timer1.start() in lines of a thread running in background, the code executed in background but the timer which is on the UI in form didn't start.

thread1.IsBackground=true;
thread1.start();

2 solutions

Solution 1

Simple: it's a Control, which means it's a UI component (even if it isn't visible) and they can only ever be accessed on the UI thread. You could - in theory - Invoke it to start it (since Invoke moves the code to the UI thread) but that would probably defeat the purpose of the BackgroundWorker!

Posted 3-Oct-16 21:52pm

OriginalGriff

v2

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lukeer · Accepted Answer · 2016-10-03T22:31:00

As OriginalGriff wrote, the System.Windows.Forms.Timer is a UI component. Usually you get it int your application by dragging one onto a Form.
But you can instatiate it in code like you would do with every ordinary class. From any thread you like. You can then call it from that thread.

But I'd rather advise to leave those timers in UI thread because there are alternavies designed to be used in other thrads: System.Timers.Timer and System.Threading.Timer.

Of cause, if you initially used Forms.Timer because the timer call will do something in the UI, you will no longer be allowed to do that from the other timers' callback functions. Instead, you will have to add a layer of invoking.

In essence, you will have to decide where to use invoke: Calls into the timer (if it is on UI thread) or out of the timer into UI thread.