C # can send emails with the .NET Framework quite easily, especially via the SMTP protocol. The SMTP protocol is a common way to send email.
Because SMTP emails require an SMTP server to send, it is probably easier to use Google’s Gmail server. Therefore, you will need a Gmail account, which is simple and free to create. Once you have a Gmail account, sending SMTP emails with C # is a breeze. The trick is to use the System.Net.Mail namespace instead of System.Web.Mail. The second namespace was replaced by System.Net starting with the .NET Framework 2.0.
But what do you do to connect to the Google server? You need a few bits of information. The first is that the Gmail SMTP server address is smtp.gmail.com. The second thing you need to know is that the C # application must connect through port 587. How do we know this? Google provides the information to developers free of charge. Other SMTP servers also provide their own address and port to connect to.
However, there is still one more thing, most SMTP servers need authentication to send their emails. This is where the Gmail account comes in. With the NetworkCredential .NET class, specify your username and password. This will authenticate your connection to the server. Just make sure your username includes @ gmail.com.
Everything is handled through the SmtpClient class. The class encapsulates some pretty powerful functions, including adding attachments and sending HTML emails. HTML emails are emails that are written with HTML code and displayed on web pages. Although it depends on the email client, most clients can read HTML emails without problems, allowing your C # application to send emails with images and formatted text. The SmtpClient class also allows developers to add headers, which can fine-tune the behavior of emails. However, keep in mind that some SMTP servers, like Google’s, will ignore certain headers and only use your account information. For example, GMail will ignore the From field setting to something else, which will automatically set the From field to your email address.
Lastly, make sure SSL is enabled in your C # application. SSL is an encryption protocol and it is absolutely necessary or the Gmail server will not accept your connection.