ASP.NET MVC中的异步操作

Question

我需要从异步操作中发送一封邮件。不明白为什么会出现下面的错误，因为我在其他项目中使用了同样的类和表单，并且没有出现错误，一切都很顺利。

错误：

异步操作方法 'EsqueciMinhaSenhaAsync' 返回一个 Task，无法同步执行。

操作：

        [AllowAnonymous]
        [HttpPost, ValidateAntiForgeryToken]
        public async Task<ActionResult> EsqueciMinhaSenhaAsync(UsuarioEsqueciMinhaSenhaViewModel vModel)
        {
            if (ModelState.IsValid)
            {
                var conteudo = "este é o conteudo do email";
                var nomeRemetente = "esse é o nome do remetente";

                if(await EmailService.SendAsync(Language.PasswordRecovery, conteudo, vModel.EmailOuUsername, nomeRemetente))
                {
                    TempData["MensagemRetorno"] = Language.EmailSendedWithSuccess;
                    return View("login");
                }
            }

            TempData["MensagemRetorno"] = Language.ErrorSendingEmail;
            return View("EsqueciMinhaSenha");
        }

我的电子邮件服务:

    public static async Task<bool> SendAsync(string assunto, string conteudo, string destinatario, string nomeDestinatario)
    {
        // Habilitar o envio de e-mail
        var appSetting = ConfigurationManager.AppSettings;

        if (appSetting != null && appSetting.Count >= 7 && !string.IsNullOrEmpty(assunto) && !string.IsNullOrEmpty(conteudo) && !string.IsNullOrEmpty(destinatario) && !string.IsNullOrEmpty(nomeDestinatario))
        {
            int port = 0;
            bool useSSl = false;

            using (var msg = new MailMessage
            {
                From = new MailAddress(appSetting["EmailFrom"], appSetting["EmailNameFrom"]),
                Body = WebUtility.HtmlEncode(conteudo)
            })
            {
                int.TryParse(appSetting["EmailPort"], out port);
                bool.TryParse(appSetting["EmailUseSSL"], out useSSl);


                msg.ReplyToList.Add(destinatario);
                msg.To.Add(new MailAddress(destinatario, nomeDestinatario));
                msg.Subject = assunto;
                msg.AlternateViews.Add(AlternateView.CreateAlternateViewFromString(msg.Body, null, MediaTypeNames.Text.Plain));
                msg.AlternateViews.Add(AlternateView.CreateAlternateViewFromString(msg.Body, null, MediaTypeNames.Text.Html));

                using (var smtpClient = new SmtpClient(appSetting["EmailServer"], port))
                {
                    var credentials = new NetworkCredential(appSetting["EmailUserName"], appSetting["EmailPassword"]);
                    smtpClient.Credentials = credentials;
                    smtpClient.EnableSsl = useSSl;
                    await smtpClient.SendMailAsync(msg);

                    return await Task.FromResult(true);
                }
            }
        }

        return await Task.FromResult(false);
    }

堆栈跟踪：

[InvalidOperationException: 异步操作方法“esqueciminhasenha”返回的是 Task，无法同步执行。]
System.Web.Mvc.Async.TaskAsyncActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 parameters) +119
System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary2 parameters) +27
System.Web.Mvc.<>c__DisplayClass15.b__12() +55 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodFilter(IActionFilter filter, ActionExecutingContext preContext, Func1 continuation) +253
System.Web.Mvc.<>c__DisplayClass17.<InvokeActionMethodWithFilters>b__14() +22 System.Web.Mvc.ControllerActionInvoker.InvokeActionMethodWithFilters(ControllerContext controllerContext, IList1 filters, ActionDescriptor actionDescriptor, IDictionary2 parameters) +189
System.Web.Mvc.ControllerActionInvoker.InvokeAction(ControllerContext controllerContext, String actionName) +521
System.Web.Mvc.Controller.ExecuteCore() +95
MusiArtist.MVC.Areas.admin.Controllers.BaseController.ExecuteCore() in F:\Backup\BitBucket\negrini.musiartist\src\MusiArtist.MVC\Areas\admin\Controllers\BaseController.cs:29 System.Web.Mvc.ControllerBase.Execute(RequestContext requestContext) +180 System.Web.Mvc.<>c__DisplayClass19.<BeginExecute>b__13() +18 System.Web.Mvc.Async.AsyncResultWrapper.<.cctor>b__0(IAsyncResult asyncResult, Action action) +15
System.Web.Mvc.Async.WrappedAsyncResult2.CallEndDelegate(IAsyncResult asyncResult) +16
System.Web.Mvc.Async.WrappedAsyncResultBase1.End() +49
System.Web.Mvc.Controller.EndExecute(IAsyncResult asyncResult) +26
System.Web.Mvc.Controller.System.Web.Mvc.Async.IAsyncController.EndExecute(IAsyncResult asyncResult) +10
System.Web.Mvc.MvcHandler.<BeginProcessRequest>b__5(IAsyncResult asyncResult, ProcessRequestState innerState) +21
System.Web.Mvc.Async.WrappedAsyncVoid1.CallEndDelegate(IAsyncResult asyncResult) +29
System.Web.Mvc.Async.WrappedAsyncResultBase`1.End() +49
System.Web.Mvc.MvcHandler.EndProcessRequest(IAsyncResult asyncResult) +28 System.Web.Mvc.MvcHandler.System.Web.IHttpAsyncHandler.EndProcessRequest(IAsyncResult result) +9
System.Web.CallHandlerExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +9765121 System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +155

- Luiz Negrini

---

请查看https://dev59.com/sIfhs4cB2Jgan1znrose。 - Nkosi

错误是关于您的操作方法本身，而不是电子邮件服务。请发布您的控制器代码。 - Panagiotis Kanavos

为了验证升级是否是问题，请创建一个新的 MVC 项目，只包含单个控制器和操作。 - Panagiotis Kanavos

@PanagiotisKanavos 我已经说过好几次了，在另一个运行相同版本的项目中是可以工作的。 - Luiz Negrini

@LuizNegrini，您能发布完整的异常信息，包括其调用堆栈吗？此外，您如何测试您的代码？您是部署到IIS还是在开发Web服务器下运行？ - Panagiotis Kanavos

Answer 1

我在控制器的“DisableAsyncSupport”方法上进行了重写，并将其getter设置为false，一切都完美地工作了！

protected override bool DisableAsyncSupport
{
    get { return false; }
}

我相信通过继承控制器（我有自己的控制器，“ControllerBase”），该方法必须表现出不同的行为。

- Luiz Negrini