Send Email Asynchronously in C#

In previous section, I introduced how to use event handler to monitor the progress. In this section, I will introduce how to send email asynchronously in C#.


In synchronous mode, once SendMail method is called, it returns to application after the method is complete. Therefore, if the runtime (it depends on the networking connection and the email size) is long, your application cannot do anything before this method ends, which results “my application is blocked or halted”. In contrast, in asynchronous mode, as BeginSendMail method works in background, this methods return to application immediately no matter the running method is complete or not.


Remarks: All of samples in this section are based on first section: Send email in a simple C# project. To compile and run the following example codes successfully, please click here to learn how to create the test project and add reference of EASendMail to your project.

[C# - Send Email Asynchronously - Example]

The following example codes demonstrate how to send email asynchronously in C#.


To get the full sample projects, please refer to Samples section.

using System;
using System.Collections.Generic;
using System.Text;
using EASendMail; //add EASendMail namespace
namespace mysendemail
    class Program
        static void Main(string[] args)
                SmtpMail oMail = new SmtpMail("TryIt");

                // Set sender email address, please change it to yours
                oMail.From = "";
                // Set recipient email address, please change it to yours
                oMail.To = "";

                // Set email subject
                oMail.Subject = "test email from c# with asynchronous mode";
                // Set email body
                oMail.TextBody = "this is a test email sent from c# project with asynchronous mode";

                // Your smtp server address
                SmtpServer oServer = new SmtpServer("");

                // User and password for ESMTP authentication
                oServer.User = "";
                oServer.Password = "testpassword";

                // Most mordern SMTP servers require SSL/TLS connection now.
                // ConnectTryTLS means if server supports SSL/TLS, SSL/TLS will be used automatically.
                oServer.ConnectType = SmtpConnectType.ConnectTryTLS;

                // If your SMTP server uses 587 port
                // oServer.Port = 587;

                // If your SMTP server requires SSL/TLS connection on 25/587/465 port
                // oServer.Port = 25; // 25 or 587 or 465
                // oServer.ConnectType = SmtpConnectType.ConnectSSLAuto;

                Console.WriteLine("start to send email in asynchronous mode...");

                SmtpClient oSmtp = new SmtpClient();
                SmtpClientAsyncResult oResult = oSmtp.BeginSendMail(
                        oServer, oMail, null, null);
                // Wait for the email sending...
                while (!oResult.IsCompleted)
                    Console.WriteLine("waiting..., you can do other thing!");
                    oResult.AsyncWaitHandle.WaitOne(50, false);

                Console.WriteLine("email was sent successfully!");
            catch (Exception ep)
                Console.WriteLine("failed to send email with the following error:");

Next Section

At next section I will introduce how to send mass emails with multiple threads in C#.



If you have any comments or questions about above example codes, please click here to add your comments.