c# - 如何实现接口(interface)返回带有空方法体的 IAsyncResult

Question

如果我想继承 ChannelBase，WCF 需要我实现 IAsyncResult OnBeginOpen(TimeSpan timeout, AsyncCallback callback, object state) 等方法。因为当 channel 打开时我无事可做，所以我宁愿将该方法主体留空。在这些空方法中，我应该返回什么作为 IAsyncResult？

Answer 1

通过将 IAsyncResult 实现添加为已完成的异步结果来解决

internal class CompletedAsyncResult : IAsyncResult
{
    public CompletedAsyncResult(object state)
    {
        this.AsyncState = state;
    }

    public object AsyncState { get; set; }

    public WaitHandle AsyncWaitHandle => new ManualResetEvent(true);

    public bool CompletedSynchronously => true;

    public bool IsCompleted => true;
}

像这样使用

protected override IAsyncResult OnBeginOpen(TimeSpan timeout, AsyncCallback callback, object state)
{
    var result = new CompletedAsyncResult(state);
    callback?.Invoke(result);
    return result;
}