Run async method 8 times in parallel

Question

How do I turn the following into a Parallel.ForEach?

public async void getThreadContents(String[] threads)
{
    HttpClient client = new HttpClient();
    Li         


        

Answer 1

Yet another alternative is using SemaphoreSlim or AsyncSemaphore (which is included in my AsyncEx library and supports many more platforms than SemaphoreSlim):

public async Task getThreadContentsAsync(String[] threads)
{
  SemaphoreSlim semaphore = new SemaphoreSlim(8);
  HttpClient client = new HttpClient();
  ConcurrentDictionary usernames = new ConcurrentDictionary();

  await Task.WhenAll(threads.Select(async url =>
  {
    await semaphore.WaitAsync();
    try
    {
      HttpResponseMessage response = await client.GetAsync(url);
      String content = await response.Content.ReadAsStringAsync();
      String user;
      foreach (Match match in regex.Matches(content))
      {
        user = match.Groups[1].ToString();
        usernames.TryAdd(user, null);
      }
      progressBar1.PerformStep();
    }
    finally
    {
      semaphore.Release();
    }
  }));
}