Question

我需要同时发送几个Post请求。为此，我将使用以下代码：

        try
        {
            using (var client = new HttpClient())
            {
                client.DefaultRequestHeaders.TryAddWithoutValidation("Authorization", $"key={customer.FCMServerKey}");

                var obj = new
                {
                    to = customer.FcmRegistrationId,
                    notification = new
                    {
                        title = push.PushTitle,
                        body = push.PushBody,
                    }
                };

                string json = JsonConvert.SerializeObject(obj);
                var data = new StringContent(json, Encoding.UTF8, "application/json");

                responseTasks.Add( client.PostAsync("https://fcm.googleapis.com/fcm/send", data));
                pushes.Add(push);
            }
        }
        catch (HttpRequestException ex)
        {

            Console.WriteLine("\nException with pushing!");
            Console.WriteLine("Message :{0} ", ex.Message);
        }

    }

    var responses = await Task.WhenAll(responseTasks);

    var count = 0;
    foreach (var response in responses)
    {
        var responseBody = await response.Content.ReadAsStringAsync();

        pushes[count].FCMResponse = responseBody;
        pushes[count].Sent = response.IsSuccessStatusCode;

        Console.WriteLine("FCM response:");
        Console.WriteLine(pushes[count].FCMResponse);

        count++;
    }

    await _pushRepository.SaveAsync(pushes);
}

如您所见，我将任务对象放入responseTasks中。然后，我将在此行的帮助下发送所有请求：

var responses = await Task.WhenAll(responseTasks);

我因此有这个例外：

未处理的异常：System.Threading.Tasks.TaskCanceledException：操作已取消。 ---> System.ObjectDisposedException：无法访问已处置的对象。对象名称：“ System.Net.Sockets.NetworkStream”。在System.Net.Sockets.NetworkStream.WriteAsync（Byte []缓冲区，Int32偏移量，Int32大小，CancellationToken cancelledToken）在System.IO.Stream.WriteAsync（Byte []缓冲区，Int32偏移量，Int32计数）在System.Net.Security.SslState.StartSendBlob（Byte []入站，Int32计数，AsyncProtocolRequest asyncRequest）在System.Net.Security.SslState.ForceAuthentication处（布尔receiveFirst，Byte []缓冲区，AsyncProtocolRequest asyncRequest）在System.Net.Security.SslState.ProcessAuthentication（LazyAsyncResult lazyResult）在System.Net.Security.SslStream.BeginAuthenticateAsClient（SslClientAuthenticationOptions sslClientAuthenticationOptions，CancellationToken cancelToken，AsyncCallback asyncCallback，对象asyncState）在System.Net.Security.SslStream。<> c.b__47_0（SslClientAuthenticationOptions arg1，CancellationToken arg2，AsyncCallback回调，对象状态）在System.Threading.Tasks.TaskFactory 1.FromAsyncImpl[TArg1,TArg2](Func 5 beginMethod，Func 2 endFunction, Action 1 endAction，TArg1 arg1，TArg2 arg2，Object state，TaskCreationOptions creationOptions处）位于System.Threading.Tasks.TaskFactory.FromAsync [TArg1，TArg2]（Func 5 beginMethod, Action 1 endMethod，TArg1 arg1，TArg2 arg2，对象状态，TaskCreationOptions creationOptions）在System.Threading.Tasks.TaskFactory.FromAsync [TArg1，TArg2]（Func 5 beginMethod, Action 1 endMethod，TArg1 arg1，TArg2 arg2，对象状态）处在System.Net.Security.SslStream.AuthenticateAsClientAsync（SslClientAuthenticationOptions sslClientAuthenticationOptions，CancellationToken cancellingToken）在System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore（Stream stream，SslClientAuthenticationOptions sslOptions，CancellationToken cancelledToken） ---内部异常堆栈跟踪的结尾--- 在System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore（Stream stream，SslClientAuthenticationOptions sslOptions，CancellationToken cancellingToken）

怎么了？

Answer 1

请检查使用方式： https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/using-statement

在您的代码中，client将在using块结束时立即被处理掉，但是responseTasks列表上仍有待处理的任务将尝试访问它。您需要在client中使用block获得结果。

System.ObjectDisposedException：无法访问已处置的对象。对象名称：“ System.Net.Sockets.NetworkStream”。使用HttpClient

1 个答案: