Xamarin-CrossPlatform POST HttpWebRequest：远程服务器返回错误：NotFound答案

【问题标题】：Xamarin-CrossPlatform POST HttpWebRequest: The remote server returned an error: NotFoundXamarin-CrossPlatform POST HttpWebRequest：远程服务器返回错误：NotFound
【发布时间】：2016-09-06 22:23:52
【问题描述】：

我在 WindowsPhone 上打开 WebResponse 时遇到问题，当我打开 WebResponse 时总是出现异常。我尝试了许多不同的方法，但是当我使用异步方法时总是会出现异常。请帮帮我。

例外：

System.Net.ni.DLL 中出现“System.Net.WebException”类型的异常，但未在用户代码中处理附加信息：远程服务器返回错误：NotFound。

private async void btLogin_Click(object sender, RoutedEventArgs e) {
        Uri uri = new Uri("http://ip-address/users/User/jan_kowalski/a");
        HttpWebRequest webRequest = WebRequest.Create(uri) as HttpWebRequest;
        webRequest.Method = "POST";
        webRequest.ContentType = "application/json";

        try {
            using (Stream ss = await webRequest.GetRequestStreamAsync()) {
                await ss.WriteAsync(new byte[0], 0, 0);
                await ss.FlushAsync();
            }

            //using (WebResponse webResponse = await webRequest.GetResponseAsync()) {       // <-- Here there is an exception or...
            //    using (StreamReader reader = new StreamReader(webResponse.GetResponseStream())) {
            //        string data = await reader.ReadToEndAsync();
            //        Log.d(TAG, data);
            //    }
            //}

            webRequest.BeginGetResponse(async (x) => {
                WebResponse webResponse = webRequest.EndGetResponse(x);         // <-- ...or here there is an exception
                StreamReader reader = new StreamReader(webResponse.GetResponseStream());
                string text = await reader.ReadToEndAsync();
                Log.d(TAG, text);
            }, null);

        } catch (WebException exc) {
            Log.e(TAG, exc.Message + "   \n" +
                exc.Source + "\n status:" +
                exc.Status + "\n" +
                exc.Response + "   \n " +
                exc.StackTrace);
        } catch (Exception ex) {
            Log.e(TAG, ex.Message + "\n stackTrace: " + ex.StackTrace);
        }
}

我注意到 Android 和 IOS 可以访问更多的方法，同步方法。当他们使用它一切正常时，我从服务器得到正确的答案。但同步方法在 Windows phone 上不可用！

            Uri uri = new Uri("http://ip-address/users/User/jan_kowalski/a");
            WebRequest webRequest = WebRequest.Create(uri);
            webRequest.Method = "POST";
            webRequest.ContentType = "application/json";
            try {
                using (Stream stream = webRequest.GetRequestStream()) {
                    stream.Write(new byte[0], 0, 0);
                }
                using (WebResponse stream = webRequest.GetResponse()) {
                    using (StreamReader reader = new StreamReader(stream.GetResponseStream())) {
                        string data = reader.ReadToEnd();
                        Console.WriteLine(data);
                    }
                }
            }catch(Exception ex) {
                Log.e(TAG, null, ex);
            }

【问题讨论】：

标签： c# xamarin httpwebrequest

【解决方案1】：

建议你试试HttpClient，界面比WebRequest干净多了：

var client = new HttpClient();
var res = await client.PostAsync("http://ip-address/users/User/jan_kowalski/a", new StringContent("hello, world"));
if (res.IsSuccessStatusCode)
{
    var response = await res.Content.ReadAsStringAsync();
}

我无法用 HttpClient 重现您的问题。

【讨论】：