Sending e-mails

Sending e-mails with ASP.NET is pretty straight forward. The .NET framework comes with an entire namespace for handling e-mails, the System.Net.Mail namespace. In the following examples, we will use two classes from this namespace: The MailMessage class, for the actual e-mail, and the SmtpClient class, for sending the e-mail.

As you may be aware, mails are sent through an SMTP server, and to send mails with the .NET framework, you will need access to an SMTP server. If you're testing things locally, the company that supplies your with Internet access, will usually have an SMTP server that you can use, and if you wish to use one of these examples on your actual website, the company that hosts your website will usually have an SMTP server that you can use. Go through the support pages to find the actual address - it's usually something along the lines of smtp.your-isp.com or mail.your-isp.com.

Once you have an accessible SMTP server, we're ready to send our very first e-mail. For the first example, all you need is an empty page, with the following code in the CodeBehind:

protected void Page_Load(object sender, EventArgs e)
{
    try
    {
        MailMessage mailMessage = new MailMessage();
        mailMessage.To.Add("your.own@mail-address.com");
        mailMessage.From = new MailAddress("another@mail-address.com");
        mailMessage.Subject = "ASP.NET e-mail test";
        mailMessage.Body = "Hello world,\n\nThis is an ASP.NET test e-mail!";
        SmtpClient smtpClient = new SmtpClient("smtp.your-isp.com");
        smtpClient.Send(mailMessage);
        Response.Write("E-mail sent!");
    }
    catch(Exception ex)
    {
        Response.Write("Could not send the e-mail - error: " + ex.Message);
    }
}

That's actually all you need to send an e-mail. We create a new MailMessage instance, add a new receiver, set the "From" address and the subject, and then we write a simple test message for the body of the e-mail. After that, we create a new instance of the SmtpClient, with the host address of the SMTP server that you may use as a parameter, and then we use the SmtpClient instance to shoot the e-mail out into cyberspace. The entire thing is surrounded by a try..catch block, just in case something goes wrong.

This was just a very basic example, but there are a lot of other options. Here is a short list with interesting ideas:

You can attach one or several files, simply by adding them to the Attachments collection. In this example, we attach a file called "image.jpg", located in the root of the ASP.NET website:

mailMessage.Attachments.Add(new Attachment(Server.MapPath("~/image.jpg")));

You can send to more than one person at the same time, simply by adding another e-mail address to the "To" collection, like this:

mailMessage.To.Add("your.own@mail-address.com");
mailMessage.To.Add("another@mail-address.com");

You can set a name for the sender - otherwise, only the e-mail address will be shown in the "From" column of the receivers e-mail client. For instance, like this:

mailMessage.From = new MailAddress("me@mail-address.com", "My Name");

You can send HTML e-mails, instead of the default plaintext mails, to use more complicated layouts. Here is a simple example:

mailMessage.IsBodyHtml = true;
mailMessage.Body = "Hello <b>world!</b>";

You can use the CC and BCC fields, just like in regular e-mail messages, like this:

mailMessage.CC.Add("me@mail-address.com");
mailMessage.Bcc.Add("me2@mail-address.com");

You can set the priority of an e-mail, like this:

mailMessage.Priority = MailPriority.High;