c# - SendAsync Smtp 邮件错误

Question

应用程序要求使用 SendAsync 而不仅仅是发送。所以我制作了一个 CEmailServer 类并设置了所有内容。到目前为止， Send 工作正常，但是当将其更改为与 SendAsync 一起使用时，它不起作用。我创建了一个在发送邮件并且 userToken 就位时调用的方法，但它一直失败。我找不到我的错误。这是我的代码:

static bool mailSent = false;

//Method for Sending with attachment.
public void SendEmail(string Address, string Recipient, string Subject, string Body, string Dir)
{
    var fromAddress = new MailAddress("someadress.kimberley@gmail.com", "My Company");
    var toAddress = new MailAddress(Address, Recipient);
    const string fromPassword = "password";
    string subject = Subject;
    string body = Body;

    var smtp = new SmtpClient
    {
        Host = "smtp.gmail.com",
        Port = 587,
        EnableSsl = true,
        DeliveryMethod = SmtpDeliveryMethod.Network,
        UseDefaultCredentials = false,
        Credentials = new NetworkCredential(fromAddress.Address, fromPassword)

    };
    using (var message = new MailMessage(fromAddress, toAddress)
    {
        Subject = subject,
        Body = body,
    })
    {
        smtp.SendCompleted += new SendCompletedEventHandler(SendCompletedCallback);
        string userState = "Test";
        message.Attachments.Add(new Attachment(Dir));
        smtp.SendAsync(message,userState);
        message.Dispose();
    }
}

//Method for Sending regular message without attachment.
public void SendEmail(string Address, string Recipient, string Subject, string Body)
{
    var fromAddress = new MailAddress("someadress.kimberley@gmail.com", "My Company");
    var toAddress = new MailAddress(Address, Recipient);
    const string fromPassword = "password";
    string subject = Subject;
    string body = Body;

    var smtp = new SmtpClient
    {
        Host = "smtp.gmail.com",
        Port = 587,
        EnableSsl = true,
        DeliveryMethod = SmtpDeliveryMethod.Network,
        UseDefaultCredentials = false,
        Credentials = new NetworkCredential(fromAddress.Address, fromPassword)

    };
    using (var message = new MailMessage(fromAddress, toAddress)
    {
        Subject = subject,
        Body = body,
    })
    {
        smtp.SendCompleted += new SendCompletedEventHandler(SendCompletedCallback);
        string userState = "Message Sent";
        smtp.SendAsync(message, userState);
        message.Dispose();
    }
}

//Method to be called when sending is complete
private static void SendCompletedCallback(object sender, AsyncCompletedEventArgs e)
{
    // Get the unique identifier for this asynchronous operation.
    String token = (string)e.UserState;

    if (e.Cancelled)
    {
        MessageBox.Show("Sending Canc");
    }
    if (e.Error != null)
    {
        MessageBox.Show("Error Sending Mail");
    }
    else
    {
        MessageBox.Show("Message sent.");
    }
    mailSent = true;
}

非常感谢!

Answer 1

您正在发送完成之前处理消息。您应该在 SendCompleted 回调事件中处理它们。这是一个 example处理客户端和消息的最佳方式。

您的代码应如下所示:

var smtp = new SmtpClient
{
    Host = "smtp.gmail.com",
    Port = 587,
    EnableSsl = true,
    DeliveryMethod = SmtpDeliveryMethod.Network,
    UseDefaultCredentials = false,
    Credentials = new NetworkCredential(fromAddress.Address, fromPassword)
};

var message = new MailMessage(fromAddress, toAddress)
{
    Subject = subject,
    Body = body,
};

smtp.SendCompleted += (s, e) => {
    SendCompletedCallback(s, e);
    smtp.Dispose();
    message.Dispose();
};
string userState = "Test";
message.Attachments.Add(new Attachment(Dir));
smtp.SendAsync(message, userState);