private static async Task<T> RunWithResultAsync<T>(this Dispatcher dispatcher, Func<T> function, DispatcherPriority priority)
{
var result = default(T);
#if UWP
await dispatcher.RunAsync(priority.ToCoreDispatcherPriority(), () =>
{
result = function();
});
#else
var tcs = new TaskCompletionSource<T>();
var dispatcherOperation = dispatcher.BeginInvoke(new Action(() =>
{
try
{
result = function();
}
catch (Exception ex)
{
tcs.SetException(ex);
}
}), priority, null);
dispatcherOperation.Completed += (sender, e) => SetResult(tcs, result);
dispatcherOperation.Aborted += (sender, e) => SetCanceled(tcs);
await tcs.Task;
#endif
return result;
}
private static Task RunAsync(this Dispatcher dispatcher, Action action, DispatcherPriority priority)
{
#if UWP
var task = dispatcher.RunAsync(priority.ToCoreDispatcherPriority(), () =>
{
action();
});
return task.AsTask();
#else
var tcs = new TaskCompletionSource<bool>();
var dispatcherOperation = dispatcher.BeginInvoke(new Action(() =>
{
try
{
action();
SetResult(tcs, true);
}
catch (Exception ex)
{
tcs.SetException(ex);
}
}), priority, null);
dispatcherOperation.Aborted += (sender, e) => SetCanceled(tcs);
return tcs.Task;
#endif
}
private static async Task<T> RunWithResultAsync<T>(this Dispatcher dispatcher, Func<CancellationToken, Task<T>> functionAsync,
CancellationToken cancellationToken, DispatcherPriority priority)
{
var tcs = new TaskCompletionSource<T>();
#if UWP
await dispatcher.RunAsync(priority.ToCoreDispatcherPriority(), async () =>
#else
var dispatcherOperation = dispatcher.BeginInvoke(new Action(async () =>
#endif
{
try
{
var task = functionAsync(cancellationToken);
await task;
if (task.IsFaulted)
{
tcs.TrySetException(task.Exception ?? new Exception("Unknown error"));
return;
}
if (task.IsCanceled)
{
SetCanceled(tcs);
return;
}
SetResult(tcs, task.Result);
}
catch (Exception ex)
{
// NOTE: in theory, it could have been already set before
tcs.TrySetException(ex);
}
#if !UWP
}), priority, null);
// IMPORTANT: don't handle 'dispatcherOperation.Completed' event.
// We should only signal to awaiter when the operation is really done
dispatcherOperation.Aborted += (sender, e) => SetCanceled(tcs);
#else
});