Is it possible to “await yield return DoSomethingAsync()”

Question

Are regular iterator blocks (i.e. \"yield return\") incompatible with \"async\" and \"await\"?

This gives a good idea of what I\'m trying to do:

asyn         


        

Answer 1

I know that I'm too late with the answer, but here is another simple solution that can be achieved with this library:
GitHub: https://github.com/tyrotoxin/AsyncEnumerable
NuGet.org: https://www.nuget.org/packages/AsyncEnumerator/
It's much simpler than Rx.

using System.Collections.Async;

static IAsyncEnumerable ProduceItems(string[] urls)
{
  return new AsyncEnumerable(async yield => {
    foreach (var url in urls) {
      var html = await UrlString.DownLoadHtmlAsync(url);
      await yield.ReturnAsync(html);
    }
  });
}

static async Task ConsumeItemsAsync(string[] urls)
{
  await ProduceItems(urls).ForEachAsync(async html => {
    await Console.Out.WriteLineAsync(html);
  });
}