LongRunningOperationWithCancellationTokenAsync

LongRunningOperationWithCancellationTokenAsync.cs

private static async Task<decimal> LongRunningOperationWithCancellationTokenAsync( int loop, CancellationToken cancellationToken )
{
    // We create a TaskCompletionSource of decimal
    var taskCompletionSource = new TaskCompletionSource<decimal>();

    // Registering a lambda into the cancellationToken
    cancellationToken.Register( () =>
    {
        // We received a cancellation message, cancel the TaskCompletionSource.Task
        taskCompletionSource.TrySetCanceled();
    } );

    var task = LongRunningOperation( loop );

    // Wait for the first task to finish among the two
    var completedTask = await Task.WhenAny( task, taskCompletionSource.Task );

    return await completedTask; // enough is enough
    
    /* the following lines are not needed anymore

    // If the completed task is our long running operation we set its result.
    if ( completedTask == task )
    {
        // Extract the result, the task is finished and the await will return immediately
        var result = await task;

        // Set the taskCompletionSource result
        taskCompletionSource.TrySetResult( result );
    }

    // Return the result of the TaskCompletionSource.Task
    return await taskCompletionSource.Task;
    */
}