如何异步发送邮件

Question

当我尝试异步发送电子邮件时，我遇到了一个问题，我发现Stackoverflow上没有帖子，但没有一个是有帮助的。我有以下代码块

public class EmailService : IIdentityMessageService
{
    public Task SendAsync(IdentityMessage message)
    {
        // Plug in your email service here to send an email.

        var mailMessage = new MailMessage
            ("me@example.com", message.Destination, message.Subject, message.Body);

        mailMessage.IsBodyHtml = true;

        var client = new SmtpClient();

        client.SendCompleted += (s, e) => client.Dispose();
        client.SendAsync(mailMessage,null);
        return Task.FromResult(0);
    }
}

我收到一封电子邮件，但在运行此代码块时出现异常

an asynchronous module or handler completed while an asynchronous operation was still pending.

有什么建议吗？

Answer 1

使用SendMailAsync而不是SendAsync

public class EmailService : IIdentityMessageService
{
    public async Task SendAsync(IdentityMessage message)
    {
        // Plug in your email service here to send an email.

        var mailMessage = new MailMessage
            ("me@example.com", message.Destination, message.Subject, message.Body);

        mailMessage.IsBodyHtml = true;

        using(var client = new SmtpClient())
        {
            await client.SendMailAsync(mailMessage);
        }
    }
}

Answer 2

-Future阅读器，处理MailMessage，或者像我喜欢的那样使用using语法！我不知道当你不处理它时，你会损失多少内存，或者它是否可以以某种方式被回收。我将发送大量的电子邮件给用户，所以我不想知道它是否会随着时间的推移而停止工作。

public class EmailService : IIdentityMessageService
        {
            public async Task SendAsync(IdentityMessage message)
            {
                // Plug in your email service here to send an email.

                using (var mailMessage = new MailMessage("me@example.com", message.Destination, message.Subject, message.Body))
                {
                    mailMessage.IsBodyHtml = true;

                    using (var client = new SmtpClient())
                    {
                        await client.SendMailAsync(mailMessage);
                    }
                }
            }
        }