您可以使用SemaphoreSlim
1作为请求数。SemaphoreSlim
允许async
使用WaitAsync
和同步方式锁定:
await _semphore.WaitAsync()
try
{
... use shared resource.
}
finally
{
_semphore.Release()
}
您还可以AsyncLock
根据Stephen Toub的出色文章《构建异步协调基元》第6部分:AsyncLock编写自己的文章。我在应用程序中做到了这一点,并允许在同一构造上进行同步和异步锁定。
用法:
// Async
using (await _asyncLock.LockAsync())
{
... use shared resource.
}
// Synchronous
using (_asyncLock.Lock())
{
... use shared resource.
}
实现方式:
class AsyncLock
{
private readonly Task<IDisposable> _releaserTask;
private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);
private readonly IDisposable _releaser;
public AsyncLock()
{
_releaser = new Releaser(_semaphore);
_releaserTask = Task.FromResult(_releaser);
}
public IDisposable Lock()
{
_semaphore.Wait();
return _releaser;
}
public Task<IDisposable> LockAsync()
{
var waitTask = _semaphore.WaitAsync();
return waitTask.IsCompleted
? _releaserTask
: waitTask.ContinueWith(
(_, releaser) => (IDisposable) releaser,
_releaser,
CancellationToken.None,
TaskContinuationOptions.ExecuteSynchronously,
TaskScheduler.Default);
}
private class Releaser : IDisposable
{
private readonly SemaphoreSlim _semaphore;
public Releaser(SemaphoreSlim semaphore)
{
_semaphore = semaphore;
}
public void Dispose()
{
_semaphore.Release();
}
}
}