# Runtime\_CompilerServices\_ICriticalNotifyCompletion

***

**1. Implementing ICriticalNotifyCompletion:**

```csharp
public class MyAsyncTask : ICriticalNotifyCompletion
{
    public void GetResult() { /* Your implementation */ }
    public void UnsafeOnCompleted(Action continuation) { /* Your implementation */ }
}
```

**2. Completing an Asynchronous Operation:**

```csharp
var task = Task.Run(() =>
{
    // Do your asynchronous work here
});

task.ContinueWith(t =>
{
    // Handle completion of the task
});
```

**3. Using ConfigureAwait() to Optimize Asynchronous Code:**

```csharp
Task.Run(async () =>
{
    int x = await Task.Delay(1000).ConfigureAwait(false);
});
```

**4. Creating a Cancellation Token Source:**

```csharp
using System.Threading;

CancellationTokenSource cts = new CancellationTokenSource();
```

**5. Implementing an Asynchronous Event Handler:**

```csharp
public async void Button_Click(object sender, EventArgs e)
{
    // Do your asynchronous work here
    await Task.Delay(1000);
}
```

**6. Using Async Lock to Control Concurrent Access:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    private readonly AsyncLock _lock = new AsyncLock();

    public async Task MyMethodAsync()
    {
        using (await _lock.LockAsync())
        {
            // Do your critical section work here
        }
    }
}
```

**7. Using SemaphoreSlim to Limit Concurrency:**

```csharp
using System.Threading;

class MyClass
{
    private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1);

    public async Task MyMethodAsync()
    {
        await _semaphore.WaitAsync();
        try
        {
            // Do your critical section work here
        }
        finally
        {
            _semaphore.Release();
        }
    }
}
```

**8. Using ReaderWriterLockSlim for Concurrent Data Structures:**

```csharp
using System.Threading;

class MyClass
{
    private readonly ReaderWriterLockSlim _lock = new ReaderWriterLockSlim();

    public int GetValue()
    {
        _lock.EnterReadLock();
        try
        {
            return _value;
        }
        finally
        {
            _lock.ExitReadLock();
        }
    }

    public void SetValue(int value)
    {
        _lock.EnterWriteLock();
        try
        {
            _value = value;
        }
        finally
        {
            _lock.ExitWriteLock();
        }
    }
}
```

**9. Using Interlocked for Atomic Operations:**

```csharp
using System.Threading;

class MyClass
{
    private int _counter;

    public void Increment()
    {
        Interlocked.Increment(ref _counter);
    }
}
```

**10. Using Volatile for Thread-Safe Data:**

```csharp
using System.Threading;

class MyClass
{
    private volatile int _counter;

    public void Increment()
    {
        _counter++;
    }
}
```

**11. Using MemoryBarrier for Consistent Memory Ordering:**

```csharp
using System.Threading;

class MyClass
{
    private int _data;

    public void Initialize()
    {
        _data = 42;
        Thread.MemoryBarrier();
    }
}
```

**12. Using SpinLock for Low-Contention Synchronization:**

```csharp
using System.Threading;

class MyClass
{
    private readonly SpinLock _lock = new SpinLock();

    public void MyMethod()
    {
        bool lockTaken = false;
        try
        {
            _lock.Enter(ref lockTaken);
            // Do your critical section work here
        }
        finally
        {
            if (lockTaken) _lock.Exit();
        }
    }
}
```

**13. Using Mutex for Exclusive Access:**

```csharp
using System.Threading;

class MyClass
{
    private readonly Mutex _mutex = new Mutex();

    public void MyMethod()
    {
        _mutex.WaitOne();
        try
        {
            // Do your critical section work here
        }
        finally
        {
            _mutex.ReleaseMutex();
        }
    }
}
```

**14. Using Semaphore for Resource Control:**

```csharp
using System.Threading;

class MyClass
{
    private readonly Semaphore _semaphore = new Semaphore(1, 1);

    public void MyMethod()
    {
        _semaphore.WaitOne();
        try
        {
            // Do your critical section work here
        }
        finally
        {
            _semaphore.Release();
        }
    }
}
```

**15. Using EventWaitHandle for Inter-Thread Communication:**

```csharp
using System.Threading;

class MyClass
{
    private readonly EventWaitHandle _event = new EventWaitHandle(false, EventResetMode.ManualReset);

    public void Signal()
    {
        _event.Set();
    }

    public void Wait()
    {
        _event.WaitOne();
    }
}
```

**16. Using Barrier for Task Synchronization:**

```csharp
using System.Threading;

class MyClass
{
    private readonly Barrier _barrier = new Barrier(2);

    public void Task1()
    {
        _barrier.SignalAndWait();
        // Continue task execution
    }

    public void Task2()
    {
        _barrier.SignalAndWait();
        // Continue task execution
    }
}
```

**17. Using CountDownEvent for Task Completion Tracking:**

```csharp
using System.Threading;

class MyClass
{
    private readonly CountdownEvent _countDown = new CountdownEvent(2);

    public void Task1()
    {
        _countDown.Signal();
    }

    public void Task2()
    {
        _countDown.Signal();
    }

    public void WaitAll()
    {
        _countDown.Wait();
    }
}
```

**18. Using ManualResetEvent for Manual Synchronization:**

```csharp
using System.Threading;

class MyClass
{
    private readonly ManualResetEvent _resetEvent = new ManualResetEvent(false);

    public void Signal()
    {
        _resetEvent.Set();
    }

    public void Wait()
    {
        _resetEvent.WaitOne();
    }
}
```

**19. Using AutoResetEvent for Automatic Reset:**

```csharp
using System.Threading;

class MyClass
{
    private readonly AutoResetEvent _autoResetEvent = new AutoResetEvent(false);

    public void Signal()
    {
        _autoResetEvent.Set();
    }

    public void Wait()
    {
        _autoResetEvent.WaitOne();
    }
}
```

**20. Using WaitHandle.WaitAll() for Multiple Event Waiting:**

```csharp
using System.Threading;

class MyClass
{
    private readonly AutoResetEvent _event1 = new AutoResetEvent(false);
    private readonly AutoResetEvent _event2 = new AutoResetEvent(false);

    public void WaitBoth()
    {
        WaitHandle.WaitAll(new WaitHandle[] { _event1, _event2 });
    }
}
```

**21. Using ThreadPool for Background Tasks:**

```csharp
using System.Threading;

class MyClass
{
    public void RunInBackground()
    {
        ThreadPool.QueueUserWorkItem(_ =>
        {
            // Do your background task here
        });
    }
}
```

**22. Using Timer for Scheduled Tasks:**

```csharp
using System.Threading;
using System.Timers;

class MyClass
{
    private readonly Timer _timer = new Timer(OnTimerCallback);

    public void StartTimer()
    {
        _timer.Interval = 1000;
        _timer.Start();
    }

    private void OnTimerCallback(object state)
    {
        // Do your scheduled task here
    }
}
```

**23. Using BackgroundWorker for Extended Background Tasks:**

```csharp
using System.ComponentModel;

class MyClass
{
    private readonly BackgroundWorker _worker = new BackgroundWorker();

    public void StartBackgroundWork()
    {
        _worker.DoWork += Worker_DoWork;
        _worker.RunWorkerAsync();
    }

    private void Worker_DoWork(object sender, DoWorkEventArgs e)
    {
        // Do your background task here
    }
}
```

**24. Using Task-Based Asynchronous Pattern (TAP):**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public async Task MyMethodAsync()
    {
        await Task.Delay(1000);
        // Do your asynchronous work here
    }
}
```

**25. Using Event-Based Asynchronous Pattern (EAP):**

```csharp
using System;
using System.Threading;

class MyClass
{
    public void MyMethod(AsyncCallback callback, object state)
    {
        ThreadPool.QueueUserWorkItem(_ =>
        {
            // Do your asynchronous work here
            callback(state);
        });
    }
}
```

**26. Using IAsyncResult and AsyncCompletedEventHandler:**

```csharp
using System;
using System.Threading;

class MyClass
{
    public IAsyncResult BeginMyMethod(AsyncCallback callback, object state)
    {
        var result = new MyAsyncResult(callback, state);
        ThreadPool.QueueUserWorkItem(_ => MyMethod(result));
        return result;
    }

    public void EndMyMethod(IAsyncResult asyncResult)
    {
        var myAsyncResult = (MyAsyncResult)asyncResult;
        // Get result from MyAsyncResult
    }

    private void MyMethod(MyAsyncResult asyncResult)
    {
        // Do your asynchronous work here
        asyncResult.InvokeCallback();
    }

    private class MyAsyncResult : IAsyncResult
    {
        private readonly AsyncCallback _callback;
        private readonly object _state;
        private bool _completed;

        public MyAsyncResult(AsyncCallback callback, object state)
        {
            _callback = callback;
            _state = state;
        }

        public bool IsCompleted => _completed;

        public WaitHandle AsyncWaitHandle => null;

        public object AsyncState => _state;

        public bool CompletedSynchronously => false;

        public void InvokeCallback()
        {
            _completed = true;
            _callback(this);
        }
    }
}
```

**27. Using await with synchronization primitives:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly Mutex _mutex = new Mutex();

    public async Task MyMethodAsync()
    {
        await _mutex.WaitAsync();
        try
        {
            // Do your critical section work here
        }
        finally
        {
            _mutex.ReleaseMutex();
        }
    }
}
```

**28. Using Task.WhenAll for Parallel Completion:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public async Task MyMethodAsync()
    {
        var task1 = Task.Delay(1000);
        var task2 = Task.Delay(2000);
        await Task.WhenAll(task1, task2);
        // Both tasks have completed
    }
}
```

**29. Using Task.WhenAny for Concurrent Completion:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public async Task MyMethodAsync()
    {
        var task1 = Task.Delay(1000);
        var task2 = Task.Delay(2000);
        var completedTask = await Task.WhenAny(task1, task2);
        // One of the tasks has completed
    }
}
```

**30. Using Parallel.ForEach for Data-Parallelism:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    private int[] _data;

    public void MyMethod()
    {
        Parallel.ForEach(_data, item =>
        {
            // Do something with each item in parallel
        });
    }
}
```

**31. Using Parallel.Invoke for Concurrency:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public void MyMethod()
    {
        Parallel.Invoke(() =>
        {
            // Do something in parallel
        }, () => {
            // Do something else in parallel
        });
    }
}
```

**32. Using Parallel.For for Loop-Level Parallelism:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    private int[] _data;

    public void MyMethod()
    {
        Parallel.For(0, _data.Length, i =>
        {
            // Do something with each element in parallel
        });
    }
}
```

**33. Using TaskFactory for Custom Task Creation:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public Task<int> MyMethodAsync()
    {
        var taskFactory = new TaskFactory();
        return taskFactory.StartNew(() =>
        {
            // Do something and return a result
            return 42;
        });
    }
}
```

**34. Using Task.FromResult for Immediate Task Creation:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public Task<int> MyMethodAsync()
    {
        return Task.FromResult(42);
    }
}
```

**35. Using Task.Run for Background Tasks:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public void MyMethod()
    {
        Task.Run(() =>
        {
            // Do something in the background
        });
    }
}
```

**36. Using Task.Wait and Task.Result for Blocking:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public int MyMethodAsync()
    {
        var task = Task.Run(() => 42);
        task.Wait();
        return task.Result;
    }
}
```

**37. Using TaskCompletionSource for Custom Task Completion:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    public async Task<int> MyMethodAsync()
    {
        var tcs = new TaskCompletionSource<int>();
        // Do something and then set the result
        tcs.SetResult(42);
        return await tcs.Task;
    }
}
```

**38. Using async-await with lock:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    private readonly object _lock = new object();

    public async Task MyMethodAsync()
    {
        lock (_lock)
        {
            // Do something synchronized
            await Task.Delay(1000);
        }
    }
}
```

**39. Using async-await with semaphore:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly SemaphoreSlim _semaphore = new SemaphoreSlim(1, 1);

    public async Task MyMethodAsync()
    {
        await _semaphore.WaitAsync();
        try
        {
            // Do something synchronized
            await Task.Delay(1000);
        }
        finally
        {
            _semaphore.Release();
        }
    }
}
```

**40. Using async-await with custom synchronization primitive:**

```csharp
using System.Threading.Tasks;

class MyClass
{
    private readonly AsyncLock _asyncLock = new AsyncLock();

    public async Task MyMethodAsync()
    {
        using (await _asyncLock.LockAsync())
        {
            // Do something synchronized
            await Task.Delay(1000);
        }
    }
}
```

**41. Using async-await with ReaderWriterLockSlim:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly ReaderWriterLockSlim _rwLock = new ReaderWriterLockSlim();

    public async Task MyMethodAsync()
    {
        _rwLock.EnterReadLock();
        try
        {
            // Do something synchronized
            await Task.Delay(1000);
        }
        finally
        {
            _rwLock.ExitReadLock();
        }
    }
}
```

**42. Using async-await with Mutex:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly Mutex _mutex = new Mutex();

    public async Task MyMethodAsync()
    {
        _mutex.WaitOne();
        try
        {
            // Do something synchronized
            await Task.Delay(1000);
        }
        finally
        {
            _mutex.ReleaseMutex();
        }
    }
}
```

**43. Using async-await with Semaphore:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly Semaphore _semaphore = new Semaphore(1, 1);

    public async Task MyMethodAsync()
    {
        _semaphore.WaitOne();
        try
        {
            // Do something synchronized
            await Task.Delay(1000);
        }
        finally
        {
            _semaphore.Release();
        }
    }
}
```

**44. Using async-await with EventWaitHandle:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly EventWaitHandle _event = new EventWaitHandle(false, EventResetMode.ManualReset);

    public async Task MyMethodAsync()
    {
        _event.WaitOne();
        // Do something synchronized
        await Task.Delay(1000);
    }

    public void Signal()
    {
        _event.Set();
    }
}
```

**45. Using async-await with Barrier:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly Barrier _barrier = new Barrier(2);

    public async Task MyMethodAsync()
    {
        await _barrier.SignalAndWaitAsync();
        // Do something synchronized
        await Task.Delay(1000);
    }
}
```

**46. Using async-await with CountdownEvent:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly CountdownEvent _countDown = new CountdownEvent(2);

    public async Task MyMethodAsync()
    {
        await _countDown.WaitAsync();
        // Do something synchronized
        await Task.Delay(1000);
    }

    public void Signal()
    {
        _countDown.Signal();
    }
}
```

**47. Using async-await with ManualResetEvent:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly ManualResetEvent _resetEvent = new ManualResetEvent(false);

    public async Task MyMethodAsync()
    {
        await _resetEvent.WaitAsync();
        // Do something synchronized
        await Task.Delay(1000);
    }

    public void Signal()
    {
        _resetEvent.Set();
    }
}
```

**48. Using async-await with AutoResetEvent:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly AutoResetEvent _autoResetEvent = new AutoResetEvent(false);

    public async Task MyMethodAsync()
    {
        await _autoResetEvent.WaitAsync();
        // Do something synchronized
        await Task.Delay(1000);
    }

    public void Signal()
    {
        _autoResetEvent.Set();
    }
}
```

**49. Using async-await with WaitHandle.WaitAll():**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    private readonly AutoResetEvent _event1 = new AutoResetEvent(false);
    private readonly AutoResetEvent _event2 = new AutoResetEvent(false);

    public async Task MyMethodAsync()
    {
        await Task.WhenAll(
            _event1.WaitAsync(),
            _event2.WaitAsync()
        );
        // Do something synchronized
        await Task.Delay(1000);
    }

    public void SignalEvent1()
    {
        _event1.Set();
    }

    public void SignalEvent2()
    {
        _event2.Set();
    }
}
```

**50. Using async-await with ThreadPool:**

```csharp
using System.Threading;
using System.Threading.Tasks;

class MyClass
{
    public async Task MyMethodAsync()
    {
        await Task.Run(() =>
        {
            // Do something in the background
            Thread.Sleep(1000);
        });
    }
}
```