private void buttonUnproperCase_Click(object sender, EventArgs e)
{
try
{
logWriter.Log("Insede the button handler.");
Task.Run(() =>
{
try
{
logWriter.Log("Trying to change prefix in non-UI thread.");
var button = (Button)sender;
button.Text = "Not so " + button.Text;
logWriter.Log("Prefix successfully changed.");
}
catch (Exception ex)
{
logWriter.Log($"It's still bad idea to change controls outside of the UI thread. Exception:\r\n{ex.Message}");
}
});
}
catch (Exception ex)
{
logWriter.Log($"Ooops, something went wrong with threading.\r\nException: {ex.Message}");
}
}
public static void ForegroundThreadWithoutJoin()
{
ThreadLogger.Log("main start");
var thread = new Thread(IntensiveOperationsService.OneSecondWork);
thread.Start();
ThreadLogger.Log("main end");
}
public static void TaskContinuations()
{
var task1 = Task.Run(() => IntensiveOperationsService.CancellableSleepingSum(1, 3));
var task2 = task1.ContinueWith(t => ThreadLogger.Log($"The sum is {t.Result}"));
var task3 = task2.ContinueWith(t => ThreadLogger.Log("Just a simple message from third task"));
ThreadLogger.Log("Waiting for simple message from third task");
//Needed to avoid mixing with other examples
task3.Wait();
}
public async void OnNavigatedTo(NavigationContext navigationContext)
{
//Debug.WriteLine($"{nameof(View1ViewModel)} OnNavigatedTo");
ThreadLogger.Log("Before loading View 1 data", GetType().Name);
Text = "Loading View 1...";
await DoSomethingAsync();
Text = "View 1 Loaded Complete!";
ThreadLogger.Log("After loading View 1 data", GetType().Name);
}
public static void CancellingTheTask()
{
var cts = new CancellationTokenSource();
var token = cts.Token;
var task1 = Task.Run(() => IntensiveOperationsService.CancellableSleepingSum(1, 10, token), token);
Thread.Sleep(2000);
ThreadLogger.Log("Cancelling the cts");
cts.Cancel();
}
public static void QueueUserWorkItemAndCancelIt()
{
ThreadLogger.Log("main start");
var cts = new CancellationTokenSource();
var token = cts.Token;
System.Threading.ThreadPool.QueueUserWorkItem(x => IntensiveOperationsService.CancellableLoop(token));
Thread.Sleep(3000);
cts.Cancel();
ThreadLogger.Log("main end");
}
public static void WaitAnyAndWaitAll()
{
var task1 = Task.Run(() => IntensiveOperationsService.CancellableSleepingSum(1, 1));
var task2 = Task.Run(() => IntensiveOperationsService.CancellableSleepingSum(2, 2));
var task3 = Task.Run(() => IntensiveOperationsService.CancellableSleepingSum(3, 3));
var index = Task.WaitAny(task1, task2, task3);
ThreadLogger.Log($"Task {index + 1} finished first");
Task.WaitAll(task1, task2, task3);
ThreadLogger.Log("All tasks finished");
}
public static void CancellationTokenWithCallback()
{
ThreadLogger.Log("main start");
var cts = new CancellationTokenSource();
var token = cts.Token;
token.Register(() => ThreadLogger.Log("token has been cancelled"));
System.Threading.ThreadPool.QueueUserWorkItem(x => IntensiveOperationsService.CancellableLoop(token));
Thread.Sleep(3000);
cts.Cancel();
ThreadLogger.Log("main end");
}
public static void SimpleTaskCreation()
{
//Create and schedule a task via static method
var task1 = Task.Run(() => IntensiveOperationsService.CancellableSleepingSum(1, 2));
//Create a new task instance and schedule it via .Start() method
var task2 = new Task <int>(n => IntensiveOperationsService.CancellableSleepingSum(2, (int)n), 2);
task2.Start();
//Create a task factory and use .StartNew() method to create and schedule a task
TaskFactory tf = new TaskFactory(/*Various options for all tasks created via this factory*/);
var task3 = tf.StartNew(() => IntensiveOperationsService.CancellableSleepingSum(3, 2));
ThreadLogger.Log($"Task 1: {task1.Result}");
ThreadLogger.Log($"Task 2: {task2.Result}");
ThreadLogger.Log($"Task 3: {task3.Result}");
}
public static void LinkedCancellationTokens()
{
ThreadLogger.Log("main start");
var cts1 = new CancellationTokenSource();
cts1.Token.Register(() => ThreadLogger.Log("cts1 cancelled"));
var cts2 = new CancellationTokenSource();
cts2.Token.Register(() => ThreadLogger.Log("cts2 cancelled"));
var cts = CancellationTokenSource.CreateLinkedTokenSource(cts1.Token, cts2.Token);
cts.Token.Register(() => ThreadLogger.Log("linked cts cancelled"));
System.Threading.ThreadPool.QueueUserWorkItem(x => IntensiveOperationsService.CancellableLoop(cts.Token));
Thread.Sleep(3000);
cts2.Cancel();
ThreadLogger.Log("main end");
}
public static void TaskThrowsExceptionWhichIsNotObserved()
{
//Adding an event handler for unobserved exceptions
TaskScheduler.UnobservedTaskException += (sender, e) =>
{
if (sender is Task task && task.Exception is AggregateException agg)
{
var messages = agg.InnerExceptions.Select(ie => ie.Message).Aggregate((a, b) => a + ", " + b);
ThreadLogger.Log($"Within event handler - {messages}");
}
};
//scheduling a task and not calling .Wait(), or accessing .Result or .Exception properties
Task.Run(() => throw new Exception("Something's wrong!"));
//ensure that the task will be garbage collected
Thread.Sleep(1000);
GC.WaitForPendingFinalizers();
GC.Collect();
}
public static void TaskAndChildTasks()
{
var parent = new Task <int[]>(() =>
{
var results = new int[3];
new Task(() => results[0] = IntensiveOperationsService.CancellableSleepingSum(1, 1), TaskCreationOptions.AttachedToParent).Start();
new Task(() => results[1] = IntensiveOperationsService.CancellableSleepingSum(2, 2), TaskCreationOptions.AttachedToParent).Start();
new Task(() => results[2] = IntensiveOperationsService.CancellableSleepingSum(3, 3), TaskCreationOptions.AttachedToParent).Start();
return(results);
});
parent.ContinueWith(x => ThreadLogger.Log($"Sum of all results: {x.Result.Sum()}"));
ThreadLogger.Log("Starting parrent task");
parent.Start();
//Needed to avoid mixing with other examples
parent.Wait();
}
public static void CancellationTokenCallbackThrowingExceptionsWithAggregation()
{
ThreadLogger.Log("main start");
var cts = new CancellationTokenSource();
var token = cts.Token;
token.Register(() => throw new Exception("foo"));
token.Register(() => throw new Exception("bar"));
System.Threading.ThreadPool.QueueUserWorkItem(x => IntensiveOperationsService.CancellableLoop(token));
Thread.Sleep(3000);
try
{
cts.Cancel(false);
}
catch (AggregateException ex)
{
ThreadLogger.Log($"main exception: {ex.GetType()} - {ex.InnerExceptions.Select(e => e.Message).Aggregate((a, b) => a + ", " + b)}");
}
ThreadLogger.Log("main end");
}
public static void QueueUserWorkItem()
{
ThreadLogger.Log("main start");
System.Threading.ThreadPool.QueueUserWorkItem(IntensiveOperationsService.OneSecondWork);
ThreadLogger.Log("main end");
}