Blocking and waiting for an event

Question

It sometimes want to block my thread while waiting for a event to occur.

I usually do it something like this:

private AutoResetEvent _autoResetEvent          


        

Answer 1

You may also try this:

class EventWaiter where TEventArgs : EventArgs
{
    private readonly Action> _unsubHandler;
    private readonly Action> _subHandler;

    public EventWaiter(Action> subHandler, Action> unsubHandler)
    {
        _unsubHandler = unsubHandler;
        _subHandler = subHandler;
    }

    protected void Handler(object sender, TEventArgs args)
    {
        _unsubHandler.Invoke(Handler);
        TaskCompletionSource.SetResult(args);
    }

    public  TEventArgs WaitOnce()
    {
        TaskCompletionSource = new TaskCompletionSource();
        _subHandler.Invoke(Handler);
        return TaskCompletionSource.Task.Result;
    }

    protected TaskCompletionSource TaskCompletionSource { get; set; } 

}

Usage:

EventArgs eventArgs = new EventWaiter((h) => { button.Click += new EventHandler(h); }, (h) => { button.Click -= new EventHandler(h); }).WaitOnce();