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POHow to use HttpClient PostAsync() with threadpool in C#?
 

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  1. POHow to use HttpClient PostAsync() with threadpool in C#?
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    <p>I'm using the following code to post an image to a server.</p> <pre><code>var image= Image.FromFile(@"C:\Image.jpg"); Task&lt;string&gt; upload = Upload(image); upload.Wait(); public static async Task&lt;string&gt; Upload(Image image) { var uriBuilder = new UriBuilder { Host = "somewhere.net", Path = "/path/", Port = 443, Scheme = "https", Query = "process=false" }; using (var client = new HttpClient()) { client.DefaultRequestHeaders.Add("locale", "en_US"); client.DefaultRequestHeaders.Add("country", "US"); var content = ConvertToHttpContent(image); content.Headers.ContentType = MediaTypeHeaderValue.Parse("image/jpeg"); using (var mpcontent = new MultipartFormDataContent("--myFakeDividerText--") { {content, "fakeImage", "myFakeImageName.jpg"} } ) { using ( var message = await client.PostAsync(uriBuilder.Uri, mpcontent)) { var input = await message.Content.ReadAsStringAsync(); return "nothing for now"; } } } } </code></pre> <p>I'd like to modify this code to run multiple threads. I've used "ThreadPool.QueueUserWorkItem" before and started to modify the code to leverage it.</p> <pre><code>private void UseThreadPool() { int minWorker, minIOC; ThreadPool.GetMinThreads(out minWorker, out minIOC); ThreadPool.SetMinThreads(1, minIOC); int maxWorker, maxIOC; ThreadPool.GetMaxThreads(out maxWorker, out maxIOC); ThreadPool.SetMinThreads(4, maxIOC); var events = new List&lt;ManualResetEvent&gt;(); foreach (var image in ImageCollection) { var resetEvent = new ManualResetEvent(false); ThreadPool.QueueUserWorkItem( arg =&gt; { var img = Image.FromFile(image.getPath()); Task&lt;string&gt; upload = Upload(img); upload.Wait(); resetEvent.Set(); }); events.Add(resetEvent); if (events.Count &lt;= 0) continue; foreach (ManualResetEvent e in events) e.WaitOne(); } } </code></pre> <p>The problem is that only one thread executes at a time due to the call to "upload.Wait()". So I'm still executing each thread in sequence. It's not clear to me how I can use PostAsync with a thread-pool.</p> <p>How can I post images to a server using multiple threads by tweaking the code above? Is HttpClient PostAsync the best way to do this?</p>
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