c# - 不允许异步锁

Question

基本上，我想向 tcp 服务器发出多个异步请求。我目前有一个工作客户端，它只同步并在每次网络调用时阻止 UI。由于几乎同时发生多个请求，我尝试这样做:

private object readonly readLock = new object(); 
public async Task UpdateDetailsAsync()
{
    //I want every request to wait their turn before requesting (using the connection) 
    //to prevent a read call from catching any data from another request
    lock (readLock)
    {
        Details details = await connection.GetDetailsAsync();
        detailsListBox.Items = details;
    }
}

我确信这不是 lock 的好用法，但这是我能想到的唯一可以让调用等待轮到它们的方法。有没有我可以用来实现这种行为的对象？我认为 Monitor 会是一样的，所以我没有尝试(我知道它们是多线程的东西，但这就是我所熟悉的......)

Answer 1

看起来你遇到的问题是线程在获取锁时会阻塞，所以你的方法不是完全异步的。要解决此问题，您可以使用 SemaphoreSlim.WaitAsync

private readonly SemaphoreSlim readLock = new SemaphoreSlim(1, 1); 
public async Task UpdateDetailsAsync()
{
    //I want every request to wait their turn before requesting (using the connection) 
    //to prevent a read call from catching any data from another request
    await readLock.WaitAsync();
    try
    {
        Details details = await connection.GetDetailsAsync();
        detailsListBox.Items = details;
    }
    finally
    {
        readLock.Release();
    }
}