Question

是否可以获取一个值，该值指示有多少线程等待获取某个对象的锁定？

Answer 1

不，但你可以在一个类中填充锁：

Interlocked.Increment

在进入柜台锁定之前

Interlocked.Decrement

获得锁定后

例如：

public sealed class SimpleCountedLock
{
    private readonly object obj = new object();

    private int counter;

    public int Counter
    {
        get
        {
            // Guaranteed to return the last value
            return Interlocked.CompareExchange(ref counter, 0, 0);
        }
    }

    public void Enter(ref bool lockTaken)
    {
        int cnt = int.MinValue;

        try
        {
            try
            {
            }
            finally
            {
                // Finally code can't be interrupted by asyncronous exceptions
                cnt = Interlocked.Increment(ref counter);
            }

            Monitor.Enter(obj, ref lockTaken);
        }
        finally
        {
            // There could be an asynchronous exception (Thread.Abort for example)
            // between the try and the Interlocked.Increment .
            // Here we check if the Increment was done
            if (cnt != int.MinValue)
            {
                Interlocked.Decrement(ref counter);
            }
        }
    }

    public void Exit()
    {
        Monitor.Exit(obj);
    }
}

使用：

SimpleCountedLock cl = new SimpleCountedLock();

然后在各种线程中：

bool lockTaken = false;

try
{
    cl.Enter(ref lockTaken);
    // Your code. The lock is taken
}
finally
{
    if (lockTaken)
    {
        cl.Exit();
    }
}

ref lockTaken的原因在于：Monitor.Enter。

如何获得等待进入锁定的线程数量？

1 个答案: