C# 是否可以获取使用监视器等待的排队线程的计数。输入？

我运行的一些单例代码不是线程安全的，需要一些时间来运行。 它偶尔会被多个用户同时调用，所以我使用Monitor来处理处理请求队列，如下所示

bool lockWasTaken = false;
try
{
    Monitor.TryEnter(lockObject, ref lockWasTaken); // returns lockWasTaken = true if it can get a lock
    if (!lockWasTaken)
    {
        log.Warn("Locked by existing request. Request is queued.");
        Monitor.Enter(lockObject, ref lockWasTaken); // Goes into the queue to access the object
    }

    // Do the Singleton processing

}
catch(Exception ex)
{
    log.Fatal(ex);
}
finally
{
    if (lockWasTaken)
    {
        Monitor.Exit(lockObject);
    }
}

这一切都很好。但我想做的是能够记录有多少排队的请求。

---

这可能吗？

感谢@Theodor Zoulias使用Interlocked类为下面的解决方案指出了正确的方向

private static readonly Object lockObject = new Object(); // just a random object used to decide whether the thread has locked the Singleton functions
private static int queueCount = 0; // tracked across multiple threads

bool lockWasTaken = false;
try
{
    // Increments the queueCount variable across multiple threads
    // https://docs.microsoft.com/en-us/dotnet/api/system.threading.interlocked.increment?view=netframework-4.8
    int currentQueueCount = Interlocked.Increment(ref queueCount);

    Monitor.TryEnter(lockObject, ref lockWasTaken); // returns lockWasTaken = true if it can get a lock
    if (!lockWasTaken)
    {
        log.Warn("Locked by existing request. Request is queued. Queue length is " + (currentQueueCount - 1).ToString()); // subtract since the first request is already processing
        Monitor.Enter(lockObject, ref lockWasTaken); // Goes into the queue to access the object
    }

    // Do the Singleton processing

}
catch(Exception ex)
{
    log.Fatal(ex);
}
finally
{
    if (lockWasTaken)
    {
        Monitor.Exit(lockObject);
    }
    // Reduce the queue count
    Interlocked.Decrement(ref queueCount);
}

---

如果（！lockwastake）{块中有一个正在更新的静态变量，该怎么办？答案是没有。您是否查看了类以及方法

Increment

和

Decrement

？您应该使用从

interlocated.Increment（ref queueCount）返回的int；

而不是

queueCount

本身，因为值可能在

TryEnter

和日志警告之间更改。增量调用返回的int始终是增量后的新值。