如何忽略发送电子邮件方法并继续执行？

Question

我正在使用 C# 发送电子邮件。当互联网可用时它工作正常，但它一次又一次地返回异常消息并在互联网连接不可用时停止执行。如果连接不可用，我如何忽略发送电子邮件并继续执行， 或任何其他合适的方法来做到这一点..

while (true)
{
    try
    {
        Thread.Sleep(50);
        MailMessage mail = new MailMessage();
        SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
        mail.From = new MailAddress("mymail");
        mail.To.Add("mymail");
        mail.Subject = "data - 1";
        mail.Body = "find attachement";
        System.Net.Mail.Attachment attachment;
        attachment = new System.Net.Mail.Attachment(filepath);
        mail.Attachments.Add(attachment);
        SmtpServer.Port = 587;
        SmtpServer.Credentials = new System.Net.NetworkCredential("myemail", "mypassword");
        SmtpServer.EnableSsl = true;
        SmtpServer.Send(mail);
    }
    catch (Exception)
    {
        MessageBox.Show("Internet Connection is not found");
    }
}  

Answer 1

任何依赖于重复尝试的解决方案都可能最终无休止地循环。

您的代码正在同步发送电子邮件，为什么不使用pickup directory send asynchronously

这会将电子邮件放入 SMTP 提取目录，并且 SMTP 服务器将通过重试一段可配置的时间来处理暂时的网络问题。

Answer 2

在没有互联网的情况下跳出循环：

while (true)
    {
        try
        {
            Thread.Sleep(50);
            MailMessage mail = new MailMessage();
            SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
            mail.From = new MailAddress("mymail");
            mail.To.Add("mymail");
            mail.Subject = "data - 1";
            mail.Body = "find attachement";
            System.Net.Mail.Attachment attachment;
            attachment = new System.Net.Mail.Attachment(filepath);
            mail.Attachments.Add(attachment);
            SmtpServer.Port = 587;
            SmtpServer.Credentials = new System.Net.NetworkCredential("myemail", "mypassword");
            SmtpServer.EnableSsl = true;
            SmtpServer.Send(mail);
        }
        catch (Exception)
        {
            MessageBox.Show("Internet Connection is not found");
            break;
        }
    }  

Answer 3

最好有一个 testconnection 方法，如果它返回 true 来发送电子邮件。比如：

while(true)
{ 
   if(TestConnection())
   {            
        SendEmail();    // you should leave the try...catch.. anyway in case 
                        // the connection failed between the TestConnection     
                        // and the SendEmail() operation. But then do not 
                        // prompt a messagebox, just swallow
        Thread.Sleep(50);       
   }
}

现在TestConnection的实现，你可以尝试从以下链接获取帮助：

enter link description here

Answer 4

试试这个：

while (true)
    {
        try
        {
            Thread.Sleep(50);
            MailMessage mail = new MailMessage();
            SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
            mail.From = new MailAddress("mymail");
            mail.To.Add("mymail");
            mail.Subject = "data - 1";
            mail.Body = "find attachement";
            System.Net.Mail.Attachment attachment;
            attachment = new System.Net.Mail.Attachment(filepath);
            mail.Attachments.Add(attachment);
            SmtpServer.Port = 587;
            SmtpServer.Credentials = new System.Net.NetworkCredential("myemail", "mypassword");
            SmtpServer.EnableSsl = true;
            SmtpServer.Send(mail);
        }
        catch (Exception ex)
        {
            MessageBox.Show("Error " + ex.InnerException);
            return false;
        }
    }  

或者您可以将 bool 设置为 true，然后检查 bool 是否为 true 或 false 外汇：

string noInterNet = "";
while (true)
        {
            try
            {
                Thread.Sleep(50);
                MailMessage mail = new MailMessage();
                SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com");
                mail.From = new MailAddress("mymail");
                mail.To.Add("mymail");
                mail.Subject = "data - 1";
                mail.Body = "find attachement";
                System.Net.Mail.Attachment attachment;
                attachment = new System.Net.Mail.Attachment(filepath);
                mail.Attachments.Add(attachment);
                SmtpServer.Port = 587;
                SmtpServer.Credentials = new System.Net.NetworkCredential("myemail", "mypassword");
                SmtpServer.EnableSsl = true;
                SmtpServer.Send(mail);
            }
            catch (Exception ex)
            {
                noInterNet = ex.InnerException;
            }
        }  

然后在代码的最后做：

if(noInterNet != "")
MessageBox.Show("Error " + noInterNet);