How to make a method exclusive in a multi-threaded context?

Question

I have a method that should be executed in an exclusive way. This is basically a multi-threaded application in which the method is called periodically by a timer, but which can also be started manually using a user action.

Take an example:

• The timer expires, so the method is called. The task may take several seconds.

• Immediately after this, the user clicks on, which should cause the same task: BAM. It does nothing since this method is already running.

I used the following solution:

public void DoRecurentJob()
{
    if(!Monitor.TryEnter(this.lockObject))
    {
        return;
    }

    try
    {
        // Do work
    }
    finally 
    {
        Monitor.Exit(this.lockObject);
    }
}

Where lockObjectdeclared as follows:

private readonly object lockObject = new object();

Change . There will be only one instance of an object that supports this method, so I updated the lock object so that it is non-static.

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Answer 1

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Answer 2

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Answer 3

: lockObject , "this.lockObject" . ( , , ), , , . , , ?

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Answer 4

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public class MyClass
{ 
    public void AccessResource()
    {
        OneAtATime(this);
    }

    private static void OneAtATime(MyClass instance) 
    { 
       if( !Monitor.TryEnter(lockObject) )
       // ...

Answer 5

, Microsoft lock Monitor . .

public class MyClass
{

  // Used as a lock context
  private readonly object myLock = new object();

  public void DoSomeWork()
  {
    lock (myLock)
    {
      // Critical code section
    }
  }
}

MyClass, :

private static readonly object myLock = new object();

Answer 6

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Answer 7

- MethodImplOptions.Synchronized , :

[MethodImpl(MethodImplOptions.Synchronized)] 
public void OneAtATime() { }

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Answer 8

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https://codereview.stackexchange.com/questions/16150/singleton-task-running-using-tasks-await-peer-review-challenge

private queued = false;
private running = false;
private object thislock = new object();

void Enqueue() {
    queued = true;
    while (Dequeue()) {
        try {
            // do work
        } finally {
            running = false;
        }
    }
}

bool Dequeue() {
    lock (thislock) {
        if (running || !queued) {
            return false;
        }
        else
        {
            queued = false;
            running = true;
            return true;
        }
    }
}