Calling methods in main thread from other threads

Question

I am trying to run 3 levels of timers at the same time in a C# application for example:

T1 will run in the beginning of the application, then on its Tick event, T2 will start and then on the tick event of T2, T3 will start. Finally, on the tick event of T3, something should be done in the main thread of the application

My problem seems to be that the code in the main thread is not working when it is being called by an other thread

What should I do to let the main thread run its functions by a call from other threads?

Class C1 { Timer T1; C2 c2; OnT1Tick() { c2.T2.start() } } Class C2 { Timer T2 C3 c3; OnT2Tick() { c3.T3.start } } Class C3 { Timer T3 OnT3Tick() { system.console.write ("something"); } } The problem is that the system.console.write is being called from the main thread and each timer is creating a new thread — user2302005, Jun 15 '13 at 11:30
@user2302005 please edit your question and copy/paste the code from the ide. nowhere i see `new` keyword. are you sure even the first timer is firing? — inquisitive, Jun 15 '13 at 11:51

VladL · Accepted Answer · 2013-10-29T11:10:00.530

32

Most probably the problem is that your main thread requires invocation. If you would run your program in debugger, you should see the Cross-thread operation exception, but at run time this exception check is disabled.

If your main thread is a form, you can handle it with this short code:

 if (InvokeRequired)
 {
    this.Invoke(new Action(() => MyFunction()));
    return;
 }

or .NET 2.0

this.Invoke((MethodInvoker) delegate {MyFunction();});

EDIT: for console application you can try following:

  var mydelegate = new Action<object>(delegate(object param)
  {
    Console.WriteLine(param.ToString());
  });
  mydelegate.Invoke("test");

edited Oct 29 '13 at 11:10

answered Jun 15 '13 at 11:44

VladL

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Actually, at last, it will be a unity3D function But currently I am working on the classes – user2302005 Jun 15 '13 at 11:49
VS 2013/Resharper 8 tells me I can simpify this to this.Invoke(new Action(MyFunction)); – Loren Pechtel Feb 03 '15 at 03:17
@VladL The console app part, of the delegate thingy doesn't work for me. I defined that variable in a class as static, and I invoke It from a timer, but the Thread is still not the main thread. – DreTaX Apr 21 '16 at 13:43
Help please, It is really needed. – DreTaX Apr 21 '16 at 18:45
@DreTaX ask the new question, it's hard to help without seeing the code – VladL Apr 21 '16 at 20:43
Oh wel.. http://stackoverflow.com/questions/36770367/c-sharp-call-methods-from-main-thread?noredirect=1#comment61118198_36770367 will include it – DreTaX Apr 22 '16 at 17:36
@VladL: this `Invoke` method, where does it belong to? which class? MSDN please? – knocte Feb 01 '19 at 03:46
@knocte long time ago... but should be Control.Invoke as the method is directly available on the windows form – VladL Feb 01 '19 at 21:12
System.Windows.Forms? – knocte Feb 02 '19 at 04:44

Calling methods in main thread from other threads

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