SMTP Authentication

It provides a set of protocols that simplify the communication of email messages between email servers. Most SMTP server names are written in the form “smtp.domain.com” or “mail.domain.com”: for example, a Gmail account will refer to smtp.gmail.com. Most email systems that send mail over the Internet use SMTP to send messages from one server to another, the messages can be retrieved with an email client using either POP or IMAP.

You must provide your email address in the place of “username@gmail.com” and the real password of your given Gmail account in the place of “password” for Network credentials.

Sending Email through Gmail in C# Windows Application

How do I send mail using the C# Windows Application?

Visual C# uses SMTP protocol for sending emails. SMTP stands for Simple Mail Transfer Protocol. Visual C# using System.Net.Mail namespace for sending mail. We can instantiate SmtpClient class and assign the Host and Port.

Using Gmail Server:

The Gmail SMTP server name is smtp.gmail.com and the port using send mail is 587. Here using Network Credential for password-based authentication.

Here we have to provide the information like our Gmail username and password, and then to address also.

The below example demonstrates how to send mail using the SmtpClient class. The following points to be noted in this are −

• We must specify the SMTP host server that you use to send e-mails. The Host and Port properties will be different for the different host servers. We will be using a Gmail server.
• We need to give the Credentials for authentication if required by the SMTP server.
• We should also provide the email address of the sender and the e-mail address or addresses of the recipients using the MailMessage.From and MailMessage.To properties, respectively.
• We should also specify the message content using the MailMessage.Body property.

Example:

In this example, we will create a simple application that would send an e-mail, here we will send an email to ourselves for testing the application. Use the following steps −

Step 1:

Open your Visual Studio > Go to File Menu > Click on New Project > Select Visual C# Windows Application > Name the Project and then > Click on OK.

Step 2:

On Form1 Take three labels, three text boxes, and one-button control from the toolbox.

Change the text properties of the labels to – ‘From:‘, ‘To:‘ and ‘Message:‘ respectively. Change the text property of the button control to ‘Send‘.

Step 3:

First of all add the following namespaces on top of the code window.

using System.Net; 
using System.Net.Mail;

Then go to Solution Explorer> Right-click on your project> then click on Add Reference >in the Add Reference dialogue box Click on the .Net Tab and select the System.Net and click on Add. After adding the reference our solution explorer window will look something like this.

Step 4:

Double click on the Send button and add the following code there.

private void button1_Click(object sender, EventArgs e)
        {
try
            {
                MailMessage msg = new MailMessage();
                msg.From = new MailAddress(textBox1.Text);
                msg.To.Add(textBox2.Text);
                msg.Body = textBox3.Text;
                SmtpClient smtp = new SmtpClient();
                smtp.Host = "smtp.gmail.com";
                System.Net.NetworkCredential ntcd = new NetworkCredential();
                ntcd.UserName = "Username@gmail.com";
                ntcd.Password = "Password";
                smtp.Credentials = ntcd;
                smtp.EnableSsl = true;
                smtp.Port = 587;
                smtp.Send(msg);
                MessageBox.Show("Your Email Has Send!");

            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
}