C# -停止使用返回不起作用

Question

这种方法有效：

HttpResponseMessage responseMessage = await GetResponseMessage(pathWithParams: $"https://api.webasd.com/crm/v3565/objects/contacts?&limit=100&after={afterValue}&archived=false");

private Task<HttpResponseMessage> GetResponseMessage(string pathWithParams = null, HttpRequestMessage requestMessage = null)
{
    var httpClient = new HttpClient();
    var bearerToken = _configuration["BEARER_TOKEN"];
    httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", bearerToken);
 
    if (pathWithParams != null)
    {
        return httpClient.GetAsync(pathWithParams);
    } 

    return httpClient.SendAsync(requestMessage);
}

但是，当我使用“使用”时，如下所示：

HttpResponseMessage responseMessage = await GetResponseMessage(pathWithParams: $"https://api.webasd.com/crm/v3565/objects/contacts?&limit=100&after={afterValue}&archived=false");

private Task<HttpResponseMessage> GetResponseMessage(string pathWithParams = null, HttpRequestMessage requestMessage = null)
{
    using (var httpClient = new HttpClient())
    {
        var bearerToken = _configuration["BEARER_TOKEN"];
        httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", bearerToken);

        if (pathWithParams != null)
        {
            return httpClient.GetAsync(pathWithParams);
        } 

        return httpClient.SendAsync(requestMessage);
    }
}

我得到以下错误：

System.Threading.Tasks.TaskCanceledException:手术被取消了。在System.Net.Http.ConnectHelper.ConnectAsync(String主机上，在System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage请求下，在Int32端口，在CancellationToken cancellationToken)，在System.Net.Http.HttpConnectionPool.CreateHttp11ConnectionAsync(HttpRequestMessage请求下，在Boolean allowHttp2，CancellationToken cancellationToken)，在System.Net.Http.HttpConnectionPool.GetHttpConnectionAsync(HttpRequestMessage请求下，在CancellationToken cancellationToken)，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求中，在System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage请求中，在Boolean，在System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage请求中，在System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage请求下，在System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage请求下，在System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage请求中，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求中，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求中，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求时，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage请求下，在System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage请求中，在System.Net.Http.HttpConnectionPool.SendWithRetryAsync(HttpRequestMessage在System.Net.Http.HttpClient.FinishSendAsyncBuffered(Task`1 sendTask，HttpRequestMessage请求，CancellationTokenSource cts，布尔disposeCts)在C:\Users\mk\Documents\project\sso\KLV.IdentityServer.Core\Services\ContactService.cs:line 309 at KLV.IdentityServer.Controller.ApiController.ContactsController.GetListOfContacts() in C:\Users\mk\Documents\project\sso\KLV.IdentityServer\Controller\ApiController\ContactsController.cs:line 64 at lambda_method(闭包，对象)在Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable.Awaiter.GetResult() at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableObjectResultExecutor.Execute(IActionResultTypeMapper映射器，ObjectMethodExecutor执行器，对象控制器，Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Logged|12_1(ControllerActionInvoker参数)在Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|10_0(ControllerActionInvoker调用程序，任务lastTask，状态下一步，作用域，对象状态，(在Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed上下文中))在Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next，作用域与作用域，对象与状态，布尔& isCompleted)在Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.g__Awaited|13_0(ControllerActionInvoker调用者，任务lastTask，状态下一步，范围，对象状态，布尔isCompleted)在Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|24_0(ResourceInvoker调用者，任务lastTask，状态下一步，作用域，对象状态，(在Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Rethrow(ResourceExecutedContextSealed上下文中))在Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.Next(State& next，作用域与作用域，对象与状态，布尔& isCompleted)在Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Awaited|19_0(ResourceInvoker调用器，任务lastTask，状态下一步，作用域，对象状态，布尔isCompleted(在Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.g__Logged|17_1(ResourceInvoker调用))在Microsoft.AspNetCore.Routing.EndpointMiddleware.g__AwaitRequestTask|6_0(Endpoint端点，任务requestTask，( Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext上下文中的ILogger记录器))，在IdentityServer4.Hosting.IdentityServerMiddleware.Invoke(HttpContext上下文中，IEndpointRouter路由器，IUserSession会话，IEventService事件(在IdentityServer4.Hosting.MutualTlsTokenEndpointMiddleware.Invoke(HttpContext上下文中)，IAuthenticationSchemeProvider机制(在Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext上下文)(在IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext上下文)(在IdentityServer4.Hosting.BaseUrlMiddleware.Invoke(HttpContext上下文)(在Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext上下文)(在Microsoft.AspNetCore.Session.SessionMiddleware.Invoke(HttpContext上下文)(在Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext上下文中))

我想使用using，有办法解决这个问题吗？

Answer 1

在await中使用GetResponseMessage

private async Task<HttpResponseMessage> GetResponseMessage(string pathWithParams = null, HttpRequestMessage requestMessage = null)
{
  using (var httpClient = new HttpClient())
  {

    var bearerToken = _configuration["BEARER_TOKEN"];
    httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", bearerToken);

    if (pathWithParams != null){
      return await httpClient.GetAsync(pathWithParams);
    } 
      return await httpClient.SendAsync(requestMessage);
    }
  }
}

有关更多信息，请参见我的关于传递异步/等待的文章。