In this article I will explain with an example, how to send email using GMAIL SMTP Server using C# and VB.Net.
 
 
App.Config AppSettings
Following are the SMTP settings which are saved inside the AppSettings section of the App.Config file.
<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <appSettings>
        <add key="Host" value="smtp.gmail.com"/>
        <add key="Port" value="587"/>
        <add key="SSL" value="true"/>
        <add key="FromEmail" value="sender@gmail.com"/>
        <add key="Username" value="sender@gmail.com"/>
        <add key="Password" value="password"/>
    </appSettings>
</configuration>
 
 
Namespaces
You will need to import the following namespaces.
C#
using System.IO;
using System.Net;
using System.Net.Mail;
using System.Configuration;
 
VB.Net
Imports System.IO
Imports System.Net
Imports System.Net.Mail
Imports System.Configuration
 
 
Sending SMTP email using Console Application
When the Program is run, the values of Recipient email address (To), Subject and Body is read as input from the User.
While the Sender email address (from) is read from the FromEmail AppSettings key.
Then all these values are set into an object of the MailMessage class.
Then an object of SmtpClient class is created and the settings of the GMAIL SMTP server i.e. Host, Username, Password and Port are read from the respective AppSetting keys.
Note: It is necessary to use the sender’s email address credentials while defining the Gmail SMTP Server Credentials as Gmail the sender’s email address must be equal to Gmail Username specified in credentials.
 
Finally the email is sent using the Send function of the SmtpClient class object.
MailMessage Class Properties
Following are the required properties of the MailMessage class.
From – Sender’s email address.
To – Recipient(s) Email Address.
CC – Carbon Copies (if any).
BCC – Blind Carbon Copies (if any).
Subject – Subject of the Email.
Body – Body of the Email.
IsBodyHtml – Specify whether body contains text or HTML mark up.
Attachments – Attachments (if any).
ReplyTo – ReplyTo Email address.
 
SmptClient Class Properties
Following are the properties of the SmtpClient class.
Host – SMTP Server URL (Gmail: smtp.gmail.com).
EnableSsl – Specify whether your host accepts SSL Connections (Gmail: True).
UseDefaultCredentials – Set to True in order to allow authentication based on the Credentials of the Account used to send emails.
Credentials – Valid login credentials for the SMTP server (Gmail: email address and password).
Port – Port Number of the SMTP server (Gmail: 587)
C#
namespace Send_Email_Console_CS
{
    class Program
    {
        static void Main(string[] args)
        {
            Console.WriteLine("Enter To Address:");
            string to = Console.ReadLine().Trim();
 
            Console.WriteLine("Enter Subject:");
            string subject = Console.ReadLine().Trim();
 
            Console.WriteLine("Enter Body:");
            string body = Console.ReadLine().Trim();
 
            using (MailMessage mm = new MailMessage(ConfigurationManager.AppSettings["FromEmail"], to))
            {
                mm.Subject = subject;
                mm.Body = body;
                mm.IsBodyHtml = false;
                SmtpClient smtp = new SmtpClient();
                smtp.Host = ConfigurationManager.AppSettings["Host"];
                smtp.EnableSsl = true;
                NetworkCredential NetworkCred = new NetworkCredential(ConfigurationManager.AppSettings["Username"], ConfigurationManager.AppSettings["Password"]);
                smtp.UseDefaultCredentials = true;
                smtp.Credentials = NetworkCred;
                smtp.Port = int.Parse(ConfigurationManager.AppSettings["Port"]);
                Console.WriteLine("Sending Email......");
                smtp.Send(mm);
                Console.WriteLine("Email Sent.");
                System.Threading.Thread.Sleep(3000);
                Environment.Exit(0);
            }
        }
    }
}
 
VB.Net
Module Module1
 
    Sub Main()
        Console.WriteLine("Enter To Address:")
        Dim [to] As String = Console.ReadLine().Trim()
 
        Console.WriteLine("Enter Subject:")
        Dim subject As String = Console.ReadLine().Trim()
 
        Console.WriteLine("Enter Body:")
        Dim body As String = Console.ReadLine().Trim()
 
        Using mm As New MailMessage(ConfigurationManager.AppSettings("FromEmail"), [to])
            mm.Subject = subject
            mm.Body = body
            mm.IsBodyHtml = False
            Dim smtp As New SmtpClient()
            smtp.Host = ConfigurationManager.AppSettings("Host")
            smtp.EnableSsl = True
            Dim NetworkCred As New NetworkCredential(ConfigurationManager.AppSettings("Username"), ConfigurationManager.AppSettings("Password"))
            smtp.UseDefaultCredentials = True
            smtp.Credentials = NetworkCred
            smtp.Port = Integer.Parse(ConfigurationManager.AppSettings("Port"))
            Console.WriteLine("Sending Email......")
            smtp.Send(mm)
            Console.WriteLine("Email Sent.")
            System.Threading.Thread.Sleep(3000)
            Environment.Exit(0)
        End Using
    End Sub
End Module
 
 
Screenshot
Send email using GMAIL SMTP Server using C# and VB.Net
 
 
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