Question

我想了解为什么会出现以下错误：

2016-02-05 12：04：16.0776 [89] FATAL ExceptionHandling.Models.EmailService + d__1.MoveNext - 发送电子邮件时出错。 - System.Net.Mail.SmtpException：发送邮件失败。 ---＆GT; System.InvalidOperationException：此时无法启动异步操作。异步操作只能在异步处理程序或模块中启动，或者在页面生命周期中的某些事件中启动。如果在执行页面时发生此异常，请确保将页面标记为＆lt;％@ Page Async =＆＃34; true＆＃34; ％取代。此异常也可能表示尝试调用＆＃34; async void＆＃34;方法，在ASP.NET请求处理中通常不受支持。相反，异步方法应该返回一个Task，调用者应该等待它。在System.Web.AspNetSynchronizationContext.OperationStarted（）在System.ComponentModel.AsyncOperation.CreateOperation（Object userSuppliedState，SynchronizationContext syncContext）在System.Net.Mail.SmtpClient.SendAsync（MailMessage消息，对象userToken） ---内部异常堆栈跟踪结束--- 在System.Net.Mail.SmtpClient.SendAsync（MailMessage消息，对象userToken）在System.Net.Mail.SmtpClient.SendMailAsync（MailMessage消息）在Kubra.Common.ExceptionHandling.Models.EmailService.d__1.MoveNext（）

当我运行本地时，它会生成电子邮件，当我在我的开发环境中运行时，再次没有问题。我将它移动到我的测试环境，突然间我遇到了异步问题。所有3个环境之间的配置是相同的，我试图理解潜在的问题，以便我可以解决它。

发生错误的代码：

public class EmailService : IEmailService
{
    private static readonly ILogger Logger = LogFactory.GetLogger();
    private readonly string _host;
    private readonly int _port;
    private readonly NetworkCredential _credentials;
    private readonly bool _enableSsl;

    public EmailService(EmailConfiguration emailSettings)
    {
        _host = emailSettings.Host;
        _port = emailSettings.PortNumber;
        _credentials = new NetworkCredential(emailSettings.Username, emailSettings.Password);
        _enableSsl = emailSettings.UseSsl;
    }

    public async Task<bool> SendEmail(EmailTemplate email)
    {
        try
        {
            using (var client = new SmtpClient
            {
                Host = _host,
                Port = _port,
                Credentials = _credentials,
                EnableSsl = _enableSsl
            })
            {
                client.Host = _host;
                client.Port = _port;
                client.Credentials = _credentials;
                client.EnableSsl = _enableSsl;
                await client.SendMailAsync(email.Message);
                return true;
            }
        }
        catch (Exception ex)
        {
            Logger.Fatal(ex, "Error occurred while sending an Email.");
            return false;
        }
    }
}

调用该类的代码：

protected void Application_Error()
{
    try
    {
        var subject = "Server Error on MVC CSR: " + Environment.MachineName;
        var email = new ErrorEmail(subject, "", serverError.StackTrace);
        _emailService = new EmailService(new ConfigEmail());
        Task.Run(() => { _emailService.SendEmail(email); }).Wait();
    }
    catch (Exception ex)
    {
        _logger.Fatal(ex, "Error occurred while sending e-mail");
    }
}

System.Net.Mail.SmtpException

0 个答案: