Best way in .NET to manage queue of tasks on a separate (single) thread

http://stackoverflow.com/questions/20056727/need-to-understand-the-usage-of-semaphoreslim

http://stackoverflow.com/questions/20904328/c-sharp-async-tasks-in-a-queue-or-waiting-list

http://stackoverflow.com/questions/25691679/best-way-in-net-to-manage-queue-of-tasks-on-a-separate-single-thread

To create an asynchronous single degree of parallelism queue of work you can simply create a SemaphoreSlim, initialized to one, and then have the enqueing method await on the acquisition of that semaphore before starting the requested work.

public class TaskQueue
{
    private SemaphoreSlim semaphore;
    public TaskQueue()
    {
        semaphore = new SemaphoreSlim(1);
    }

    public async Task<T> Enqueue<T>(Func<Task<T>> taskGenerator)
    {
        await semaphore.WaitAsync();
        try
        {
            return await taskGenerator();
        }
        finally
        {
            semaphore.Release();
        }
    }
    public async Task Enqueue(Func<Task> taskGenerator)
    {
        await semaphore.WaitAsync();
        try
        {
            await taskGenerator();
        }
        finally
        {
            semaphore.Release();
        }
    }
}

Of course to have a fixed degree of parallelism other than one simply initialize the semaphore to some other number.