Отправка писем через Gmail в .NET: Полное руководство

using System;
using System.Net;
using System.Net.Mail;
using System.Threading.Tasks;

public class GmailEmailSender
{
    private readonly string _email;
    private readonly string _appPassword;
    private readonly string _smtpHost = "smtp.gmail.com";
    private readonly int _smtpPort = 587;

    public GmailEmailSender(string email, string appPassword)
    {
        _email = email;
        _appPassword = appPassword;
    }

    public async Task SendEmailAsync(string toEmail, string subject, string body)
    {
        using (var client = new SmtpClient(_smtpHost, _smtpPort))
        {
            client.UseDefaultCredentials = false;
            client.Credentials = new NetworkCredential(_email, _appPassword);
            client.EnableSsl = true;
            client.DeliveryMethod = SmtpDeliveryMethod.Network;

            using (var message = new MailMessage(_email, toEmail))
            {
                message.Subject = subject;
                message.Body = body;
                message.IsBodyHtml = true;

                await client.SendMailAsync(message);
            }
        }
    }
}

var emailSender = new GmailEmailSender("yourbandshow@gmail.com", "your-16-character-app-password");
await emailSender.SendEmailAsync("band-contact@example.com",
    "Featured on The Band Show",
    "Congratulations! Your band has been featured on our show...");

Install-Package MailKit

using System;
using System.Threading.Tasks;
using MailKit.Net.Smtp;
using MimeKit;

public class AdvancedGmailEmailSender
{
    private readonly string _email;
    private readonly string _appPassword;
    private readonly string _smtpHost = "smtp.gmail.com";
    private readonly int _smtpPort = 587;

    public AdvancedGmailEmailSender(string email, string appPassword)
    {
        _email = email;
        _appPassword = appPassword;
    }

    public async Task SendEmailAsync(string toEmail, string subject, string body,
        bool isHtml = true, MimeEntity attachment = null)
    {
        var message = new MimeMessage();
        message.From.Add(new MailboxAddress("The Band Show", _email));
        message.To.Add(new MailboxAddress("", toEmail));
        message.Subject = subject;

        var builder = new BodyBuilder();

        if (isHtml)
        {
            builder.HtmlBody = body;
        }
        else
        {
            builder.TextBody = body;
        }

        if (attachment != null)
        {
            builder.Attachments.Add(attachment);
        }

        message.Body = builder.ToMessageBody();

        using (var client = new SmtpClient())
        {
            await client.ConnectAsync(_smtpHost, _smtpPort, MailKit.Security.SecureSocketOptions.StartTls);
            await client.AuthenticateAsync(_email, _appPassword);
            await client.SendAsync(message);
            await client.DisconnectAsync(true);
        }
    }

    public async Task SendEmailWithAttachmentAsync(string toEmail, string subject, string body,
        string filePath, string fileName)
    {
        var attachment = new MimePart()
        {
            Content = new MimeContent(System.IO.File.OpenRead(filePath)),
            ContentDisposition = new ContentDisposition(ContentDisposition.Attachment),
            ContentTransferEncoding = ContentEncoding.Base64,
            FileName = fileName
        };

        await SendEmailAsync(toEmail, subject, body, true, attachment);
    }
}

var emailSender = new AdvancedGmailEmailSender("yourbandshow@gmail.com", "your-16-character-app-password");

// Отправка простого письма
await emailSender.SendEmailAsync("band-contact@example.com",
    "Featured on The Band Show",
    "<h1>Congratulations!</h1><p>Your band has been featured on our show...</p>");

// Отправка письма с вложением
await emailSender.SendEmailWithAttachmentAsync("band-contact@example.com",
    "Press Kit - Featured Band",
    "Please find our press kit attached...",
    "press-kit.pdf",
    "band-press-kit.pdf");

{
  "GmailSettings": {
    "Email": "yourbandshow@gmail.com",
    "AppPassword": "your-16-character-app-password",
    "SmtpHost": "smtp.gmail.com",
    "SmtpPort": 587,
    "EnableSsl": true
  }
}

using System;
using System.Threading.Tasks;
using Microsoft.Extensions.Configuration;

public class Program
{
    public static async Task Main(string[] args)
    {
        // Загрузка конфигурации
        var config = new ConfigurationBuilder()
            .AddJsonFile("appsettings.json")
            .AddEnvironmentVariables()
            .Build();

        var gmailSettings = config.GetSection("GmailSettings");

        // Инициализация отправителя писем
        var emailSender = new AdvancedGmailEmailSender(
            gmailSettings["Email"],
            gmailSettings["AppPassword"]
        );

        // Пример: отправка письма группе
        var bandContact = new BandContact
        {
            Name = "The Rockers",
            Email = "contact@therockersband.com",
            FeaturedDate = DateTime.Now.AddDays(1),
            Genre = "Rock"
        };

        try
        {
            await SendFeaturedBandEmail(emailSender, bandContact);
            Console.WriteLine("Email sent successfully!");
        }
        catch (Exception ex)
        {
            Console.WriteLine($"Error sending email: {ex.Message}");
        }
    }

    private static async Task SendFeaturedBandEmail(AdvancedGmailEmailSender sender, BandContact band)
    {
        var subject = $"🎸 Congratulations! {band.Name} Featured on The Band Show";

        var body = $@"
        <html>
        <body>
            <h1>Featured Band Announcement</h1>
            <p>Hello {band.Name},</p>
            <p>We're excited to announce that your band will be featured on <strong>The Band Show</strong> on {band.FeaturedDate:dddd, MMMM dd}!</p>
            <p><strong>Genre:</strong> {band.Genre}</p>
            <p>We'll be highlighting your latest single and discussing your journey in the music industry.</p>
            <p>Please reply to this email with any promotional materials you'd like us to include.</p>
            <p>Best regards,<br>The Band Show Team</p>
        </body>
        </html>";

        await sender.SendEmailAsync(band.Email, subject, body);
    }
}

public class BandContact
{
    public string Name { get; set; }
    public string Email { get; set; }
    public DateTime FeaturedDate { get; set; }
    public string Genre { get; set; }
}