c# - Timer in Portable Library

Question

I can't find a timer in portable library / Windows Store. (Targeting .net 4.5 and Windows Store aka Metro)

Does any have an idea on how to created some kind of timing event?

I need somekind of a stopwatch, so this should refreshn once a second or so

Answer 1

Update: We have fixed this in Visual Studio 2013. Portable libraries targeting Store (Windows 8.1) and .NET Framework 4.5.1 projects can now reference Timer.

This is unfortunate case of where our implementation details are leaking to the user. When you target just .NET 4.5 and Windows Store apps, we actually cause you to build against something different then when you target a down-level platform (.NET 4, SL 4/5, Phone 7.x). We try treat these two as the same, but limited changes underneath start to leak (such as Timer, and Reflection). We cover some of this here: http://channel9.msdn.com/Shows/Going+Deep/NET-45-David-Kean-and-Marcea-Trofin-Portable-Libraries.

We'll look at fixing this in a future version. Until then, you have a couple of workarounds:

1) Implement your own version of Timer using Task.Delay, here's a quick copy that we're using internally:

internal delegate void TimerCallback(object state);

internal sealed class Timer : CancellationTokenSource, IDisposable
{
    internal Timer(TimerCallback callback, object state, int dueTime, int period)
    {
        Contract.Assert(period == -1, "This stub implementation only supports dueTime.");
        Task.Delay(dueTime, Token).ContinueWith((t, s) =>
        {
            var tuple = (Tuple<TimerCallback, object>)s;
            tuple.Item1(tuple.Item2);
        }, Tuple.Create(callback, state), CancellationToken.None,
            TaskContinuationOptions.ExecuteSynchronously | TaskContinuationOptions.OnlyOnRanToCompletion,
            TaskScheduler.Default);
    }

    public new void Dispose() { base.Cancel(); }
}

2) Downgrade your project to .NET 4.0 and Windows Store apps, which will give you access to Timer.

3) Create a new project targeting .NET 4.0 and Windows Store apps, and put the code that requires timer in that. Then reference that from the .NET 4.5 and Windows Store apps project.

As a side note, I've filed a work item for myself over on PclContrib site to add Timer support: http://pclcontrib.codeplex.com/workitem/12513.