Sending emails in .Net using C# and SMTP

Recently I bumped into forum thread that asked how to send emails in .Net using C#, so I decided to take a look of that.
I will demonstrate how to send email by using SMTP and Google's GMail account.

First we need to have a few prerequisites fulfilled.

1. The SMTP host server that you use to send e-mail. We'll use GMail, and its host address is "smtp.gmail.com", and port 587.
2. Do we need to enable SSL? In this case, yes we are required to use SSL, because GMail uses it.
3. Credentials for authentication, if required by the SMTP server. GMail needs to have those, so we need to pass our username and password.
4. The e-mail address of the sender. This is what goes to From-field.
5. The e-mail address or addresses of the recipients. This is what goes to To-field.
6. The message content, whatever you want to send.

Below is a working, simple code example of how to send email using C# and SMTP.
Basically the flow of code goes like this:

• First, we create a simple email message using System.Net.Mail.MailMessage.
• You can set messge type to HTML if you want, in this sample it is commented out.
• Also you can add attachments, there's a commented line in the code that does it.
• Then we initialize SMTP-client using GMail SMTP address and port 587.
• GMail uses SSL, so we need to enable it. Also we need to authenticate to our account, and we need to set NetworkCredentials for that.
• Then we just send message and that's it (hopefully) :)
• Possible exceptions are caught and we can use that information to take a look what went wrong.

That's it!

If you want further reading, check out MSDN's SmtpClient Class

    1 using System;

    2 using System.Net.Mail;

    3 using System.Net;

    4 

    5 namespace SmtpTest

    6 {

    7   class Program

    8   {

    9     static void Main(string[] args)

   10     {

   11       Console.WriteLine("Sending test message...");

   12       CreateTestMessage("smtp.gmail.com", 587);

   13       Console.WriteLine("OK");

   14       Console.ReadLine();

   15     }

   16 

   17     public static void CreateTestMessage(string server, int port)

   18     {

   19       // message info

   20       string to = "*****.*****@gmail.com"; // put recipient

   21       string from = "*****.*****@gmail.com"; // put sender email here

   22       string subject = "SMTP client using GMail."; // message subject

   23       string body = "This is our test message, w00t!"; // message body

   24 

   25       MailMessage message = new MailMessage(from, to, subject, body);

   26 

   27       // Uncomment rows below if you want to send attachment 

   28       //message.Attachments.Add(

   29       //  new Attachment(@"C:\AttachmentFolder\AttachmentFile.txt"));

   30 

   31       // Uncomment row below if you want to send HTML-message

   32       //message.IsBodyHtml = true;

   33 

   34       // Initialize SMTP client

   35       SmtpClient client = new SmtpClient(server, port);

   36 

   37       // enable SSL

   38       client.EnableSsl = true;

   39 

   40       // Credentials are necessary if the server requires the client 

   41       // to authenticate before it will send e-mail on the client's behalf.

   42       //client.Credentials = CredentialCache.DefaultNetworkCredentials;

   43       // Here we define our network credetials (username and password)

   44       NetworkCredential SmtpUserInfo = 

   45         new NetworkCredential("your.username@gmail.com", "password");

   46 

   47       // Set the credentials

   48       client.Credentials = SmtpUserInfo;

   49 

   50       try

   51       {

   52         // send message

   53         client.Send(message);

   54       }

   55       // catch possible exceptions

   56       catch (SmtpException se)

   57       {

   58         Console.WriteLine(

   59           "SmtpException caught in CreateTestMessage(): {0}", se.ToString());

   60       }

   61       catch (Exception e)

   62       {

   63         Console.WriteLine(

   64           "Exception caught in CreateTestMessage(): {0}", e.ToString());

   65       }

   66     }

   67 

   68   }

   69 }