Use the async method in a sync call
From: SO
.Net 4.5
Just use this:
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// For Task<T>: will block until the task is completed... var result = task.Result; // For Task (not Task<T>): task2.RunSynchronously(); |
.Net 4.0
Use this:
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var x = (IAsyncResult)task; task.Start(); x.AsyncWaitHandle.WaitOne(); |
…or this:
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task.Start(); task.Wait(); |
And AsyncHelper is also helpful:
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public static class AsyncHelpers { /// <summary> /// Execute's an async Task<T> method which has a void return value synchronously /// </summary> /// <param name="task">Task<T> method to execute</param> public static void RunSync(Func<Task> task) { var oldContext = SynchronizationContext.Current; var synch = new ExclusiveSynchronizationContext(); SynchronizationContext.SetSynchronizationContext(synch); synch.Post(async _ => { try { await task(); } catch (Exception e) { synch.InnerException = e; throw; } finally { synch.EndMessageLoop(); } }, null); synch.BeginMessageLoop(); SynchronizationContext.SetSynchronizationContext(oldContext); } /// <summary> /// Execute's an async Task<T> method which has a T return type synchronously /// </summary> /// <typeparam name="T">Return Type</typeparam> /// <param name="task">Task<T> method to execute</param> /// <returns></returns> public static T RunSync<T>(Func<Task<T>> task) { var oldContext = SynchronizationContext.Current; var synch = new ExclusiveSynchronizationContext(); SynchronizationContext.SetSynchronizationContext(synch); T ret = default(T); synch.Post(async _ => { try { ret = await task(); } catch (Exception e) { synch.InnerException = e; throw; } finally { synch.EndMessageLoop(); } }, null); synch.BeginMessageLoop(); SynchronizationContext.SetSynchronizationContext(oldContext); return ret; } private class ExclusiveSynchronizationContext : SynchronizationContext { private bool done; public Exception InnerException { get; set; } readonly AutoResetEvent workItemsWaiting = new AutoResetEvent(false); readonly Queue<Tuple<SendOrPostCallback, object>> items = new Queue<Tuple<SendOrPostCallback, object>>(); public override void Send(SendOrPostCallback d, object state) { throw new NotSupportedException("We cannot send to our same thread"); } public override void Post(SendOrPostCallback d, object state) { lock (items) { items.Enqueue(Tuple.Create(d, state)); } workItemsWaiting.Set(); } public void EndMessageLoop() { Post(_ => done = true, null); } public void BeginMessageLoop() { while (!done) { Tuple<SendOrPostCallback, object> task = null; lock (items) { if (items.Count > 0) { task = items.Dequeue(); } } if (task != null) { task.Item1(task.Item2); if (InnerException != null) // the method threw an exeption { throw new AggregateException("AsyncHelpers.Run method threw an exception.", InnerException); } } else { workItemsWaiting.WaitOne(); } } } public override SynchronizationContext CreateCopy() { return this; } } } |