static async Task Main(string[] args)
{
ExploreAsyncAwait.output = Output;
Console.WriteLine("Which Exercise to run? (1 - )");
int result;
while (!int.TryParse(Console.ReadKey().KeyChar.ToString(), out result))
{
Console.WriteLine("Invalid Entry");
}
switch (result)
{
case 1:
// Exercise 1 - Baseline
await ExploreAsyncAwait.AsyncAwait_A();
break;
case 2:
// Exercise 2 - Task Debugger Window
await ExploreAsyncAwait.AsyncAwait_A(pause : 10000);
break;
case 3:
// Exercise 3 - Don't await
// Note the warning - Don't ignore these
ExploreAsyncAwait.AsyncAwait_A();
break;
case 4:
// Exercise 4 - Don't await, exception lost
ExploreAsyncAwait.ThrowException();
break;
case 6:
// Exercise 4 - .Wait()
// Works
ExploreAsyncAwait.AsyncAwait_A(pause: 5000).Wait();
break;
case 0:
break;
default:
Console.WriteLine("Incorrect");
Console.ReadKey();
break;
}
Console.WriteLine("Done");
Console.ReadKey();
}
public void AsyncAwaitExercise7_Click(object sender, RoutedEventArgs e)
{
Output("Exercise 7");
// Exercise 7 - .Wait() with ConfigureAwait(false)
// Deadlock resolved the correct way using ConfigureAwait(false)
// UI Thread Blocked
// Note the log - Different thread completes the task (Logical Execution 7+) that the main thread is waiting for to complete alleviating the deadlock
ExploreAsyncAwait.AsyncAwait_A(continueOnCapturedSynchronizationContext: false, pause: 5000)
.Wait();
Messages.Add("Exercise 7 Done");
}
public async void AsyncAwaitExercise17_Click(object sender, RoutedEventArgs e)
{
// Exercise 17
// Note the values of AsyncLocal in the output window
// This is because AsyncLocal is within a container within ExecutionContext
// Execution.Run is part of back - end mechanics of asynchronous forks(await, Task.Run)
// Not any real world value - Just bringing together the concepts
// And driving home the fact that these are instances of object like any other
// This is the type of work Async / Await keywords are instructing the compiler to do
var sc = SynchronizationContext.Current;
await Task.Run(async() =>
{
// We are NOT on the UI thread. SynchronizationContext.Current is null
Debug.WriteLine($"ThreadID: {Thread.CurrentThread.ManagedThreadId} SynchoronizationContext == null: {(SynchronizationContext.Current == null)}");
await ExploreAsyncAwait.AsyncAwait_A();
TaskCompletionSource <object> taskCompletionSource = new TaskCompletionSource <object>();
// Yet, using SynchronizationContext of the UI Thread and ExecutionContext we can run
// in the same context as AsyncAwait_C
sc.Post((o) =>
{
// Spot A
// We are now on the UI thread
ExecutionContext.Run(ExploreAsyncAwait.executionContextC_Capture, (eo) =>
{
// AsyncLocal now has the same values as AsyncAwait_C
ExploreAsyncAwait.Log(11, Output);
// And safely interact with UI controls
Output("Exercise 17...");
}, null);
taskCompletionSource.SetResult(null);
}, null);
// Without this we to Spot B before we get to Spot A
await taskCompletionSource.Task;
// Spot B
});
}
