Function in multithreading

Question

I have two threads t1 and t2. I get information in t1 and based on it I want to call function in t2 which will work in t2. How can I do it?

Edit:

t2 is thread with c# form. t1 is working in a loop and it gets information that t2 should call function. I think that shared objects won't work, because t2 doesn't work in a loop, so I can't check if some object has changed.

create a new object inheriting said object and add event handling while maintaining the lock pattern? — Chad Harrison, Jun 07 '11 at 14:08

score 2 · Accepted Answer · edited May 23 '17 at 10:00

2

Share the object between both threads (for example a member of a class where both threads run) and access it using the lock pattern:

object _someobject; // as a member for example

...

lock (_someobject)
{
// manipulate the object
}

This ensures object consistency with avoiding both threads interacting with the shared object at the same time.

Another option would be to use a MethodInvoker if one of the threads is a GUI thread for example.

edited May 23 '17 at 10:00

Community

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answered Jun 07 '11 at 13:52

jdehaan

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You could use a shared/static variable that both threads can touch using a lock. – CodingBarfield Jun 07 '11 at 13:56
Yes, the object could also be static, but then take care, it is global. Still an option if you think about system or application settings for example. – jdehaan Jun 07 '11 at 13:59
Ok, MethodInvoker helped. Thanks. – vesper Jun 07 '11 at 14:09

score 2 · Answer 2 · answered Jun 07 '11 at 14:06

I believe the proper way would be to use Invoke or BeginInvoke. You call it on t1, and it gets executed on t2. You need to have a reference to some control running in t2, e.g., the form itself.

You can include the data into the closure, which you invoke in t2.

score 0 · Answer 3 · answered Jun 07 '11 at 13:55

0

I envision using a volatile variable to store the information found by t1 while t2 loops using an exception until the desired informaiton is found. But I could be wrong.

answered Jun 07 '11 at 13:55

Chad Harrison

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volatile would be ok for fields only, not for objects in general. – jdehaan Jun 07 '11 at 14:00
Point. A mention of objets would have my useful on my part. "Fools Despise Wisdom, Instruction, and Correction" – Chad Harrison Jun 07 '11 at 14:12

dashton · Answer 4 · 2011-06-07T15:42:26.807

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You would use Monitor.Wait and Pulse. They will share a locking object and a signalling variable. The waiting thread would be blocked until signaled (pulsed by working thread). e.g:

    bool _go;
lock (_locker)
            {
                while (!_go) Monitor.Wait(_locker);

            }
            CallFunc();

Working thread:

   // do work here
   DoWork();
   lock (_locker)
        {
            _go = true;
            Monitor.PulseAll(_locker);
        }

edited Jun 07 '11 at 15:42

answered Jun 07 '11 at 15:27

dashton

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The thread t2 where the function should be executed is a GUI thread. You cannot do long `Wait`s there. – Vlad Jun 07 '11 at 19:30
You are correct, but he doesn't say actually say UI thread. I assumed they are a couple of worker threads. Anyway, it is fairly pointless trying to write code to solve a problem, where the problem isn't clear because the OP didn't post any code. Lesson learned. :-| – dashton Jun 08 '11 at 07:44
anyway, we are here to help, and in many cases answer requires some guesswork. With guessing, one cannot make a reliable solution. – Vlad Jun 08 '11 at 11:16

Function in multithreading

Edit:

4 Answers4