gistfile1.cs

        /// <summary>
        /// Executes passed task (probably result of async method call) on a Dispatcher as
        /// synchronous one, but without Wait() and risk of deadlock, using new dispatcher frame
        /// that is finished as a continuation of passed task.
        /// 
        /// You should still await the task returned back if you want correct exception propagation.
        /// 
        /// Note that you can execute this method only if you're in a WPF dispatcher's context,
        /// otherwise it will throw an exception.
        /// </summary>
        public static Task ExecuteSynchronouslyOnDispatcher(this Task task)
        {
            if (!(SynchronizationContext.Current is DispatcherSynchronizationContext))
                throw new InvalidOperationException("This method should be called only from UI thread");

            var dispatcherFrame = new DispatcherFrame();
            task.ContinueWith(_ => { dispatcherFrame.Continue = false; });
            Dispatcher.PushFrame(dispatcherFrame);
            return task;
        }