Why dont receive data if i have await

Asked Sep 05 '22 at 09:19

Active Sep 05 '22 at 09:33

Viewed 44 times

i would like understand how its possible. I have in my project one linq cannot wait for response of api of twitch, and i would like understand why cannot waiting?

System.Threading.Timer _timer = new System.Threading.Timer(TimerCallback, null, 0, 120000);

private static async void TimerCallback(Object o)
{
    Console.WriteLine(DateTime.Now);

    lstTwitch.ToList().ForEach(async item =>
    {
        if (item.PathsImagem == null)
            item.PathsImagem = await Twitch.CollectImage(item.idUser.ToString());
        TwitchStream dataStream = await Twitch.CollectDataOfStream(item.idUser.ToString());
        if (Convert.ToDateTime(dataStream.started_at) != Convert.ToDateTime(item.UltimaStream))
        {

        }
    });
}

Twitch.CollectDataOfStream:

The problem is not in request api, but is the time of linq give to receive data. When start request on api he return on line of TwitchStream dataStream = await Twitch.CollectDataOfStream(item.idUser.ToString());

edited Sep 05 '22 at 09:33

Enigmativity

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asked Sep 05 '22 at 09:19

Carl

Side note: `async void` often is a *bad practice*, `async Task` is a better signature here – Dmitry Bychenko Sep 05 '22 at 09:22
@AmanB no... but th – Carl Sep 05 '22 at 09:28
@DmitryBychenko i know but my project need async void "System.Threading.Timer _timer = new System.Threading.Timer(TimerCallback, null, 0, 120000);" because the function where i call is static – Carl Sep 05 '22 at 09:29
1

@Carl - Did you notice the compiler warning that your `async` method contains no `await`? – Enigmativity Sep 05 '22 at 09:32
@Enigmativity no? But i have await before the call – Carl Sep 05 '22 at 09:34
@Carl - No, you do not. In the `private static async void TimerCallback(Object o)` method you do not have an `await`. Only in the `async item =>` anonymous method do you have any awaits. – Enigmativity Sep 05 '22 at 09:34
The current code starts a bunch of tasks and never awaits them. In .NET (Core) 5 and later you can use `await Parallel.Foreach(lstTwitch,async item=>{....})` to asynchronously process multiple items concurrently – Panagiotis Kanavos Sep 05 '22 at 09:39
@Enigmativity what can i do? I cannot remove void because the main() is static – Carl Sep 05 '22 at 09:42
@Carl - It won't solve your problem, but the signature of your method should be `private static void TimerCallback(Object o)` to avoid the compiler warning. – Enigmativity Sep 05 '22 at 09:43
@Carl - What type is `idUser`? – Enigmativity Sep 05 '22 at 09:45
@Enigmativity int – Carl Sep 05 '22 at 09:53

Why dont receive data if i have await

0 Answers0