我们有一些(同步)电子邮件代码,创建一个类来创建一个 SmtpClient,并发送电子邮件。 SmtpClient 不会被重用; 然而,我们偶尔会遇到以下异常:
System.Web.HttpUnhandledException (0x80004005): Exception of type 'System.Web.HttpUnhandledException' was thrown. ---> System.InvalidOperationException: An asynchronous call is already in progress. It must be completed or canceled before you can call this method.
at System.Net.Mail.SmtpClient.Send(MailMessage message)
at EmailSender.SendMail(MailAddress fromMailAddress, string to, String subject, String body, Boolean highPriority) in ...\EmailSender.cs:line 143
代码长这样:
// ...
var emailSender = new EmailSender();
emailSender.SendMail(toEmail, subject, body, true);
// emailSender not used past this point
// ...
public class EmailSender : IEmailSender
{
private readonly SmtpClient smtp;
public EmailSender()
{
smtp = new SmtpClient();
}
public void SendMail(MailAddress fromMailAddress, string to, string subject, string body, bool highPriority)
{
if (fromMailAddress == null)
throw new Exception();
if (to == null)
throw new ArgumentException("No valid recipients were supplied.", "to");
// Mail initialization
var mailMsg = new MailMessage
{
From = fromMailAddress,
Subject = subject,
Body = body,
IsBodyHtml = true,
Priority = (highPriority) ? MailPriority.High : MailPriority.Normal
};
mailMsg.To.Add(to);
smtp.Send(mailMsg);
}
}