【C#】IMAPサーバーからメールを受信する方法を（MailKit）

public class MailService
{
    private readonly Mail _mail;

    public MailService(Mail mail)
    {
        _mail = mail;
    }

    public async Task ReceiveMailAsync(string FolderPath)
    {
        using (var imap = new MailKit.Net.Imap.ImapClient())
        {
            try
            {
                // IMAPサーバの接続
                await imap.ConnectAsync(_mail.ImapHost, _mail.ImapPort, SecureSocketOptions.SslOnConnect);
                Debug.WriteLine("接続成功");

                // POP3サーバの認証  
                await imap.AuthenticateAsync(_mail.UserName, _mail.Password);
                Debug.WriteLine("認証成功");

                // ReadOnlyでInboxを開く
                await imap.Inbox.OpenAsync(FolderAccess.ReadOnly);

                // すべてのメールを取得
                var uids = await imap.Inbox.SearchAsync(SearchQuery.All);

                foreach (var uid in uids)
                {
                    var message = await imap.Inbox.GetMessageAsync(uid);

                    // 送信元を取得する
                    Debug.WriteLine($"送信元：" +
                        $"{string.Join(",", message.From.OfType<MailboxAddress>()
                                 .Select(f => $"{f.Name} <{f.Address}>")
                                 .ToArray())}");

                    // 宛先を取得する
                    Debug.WriteLine($"宛先：" +
                        $"{string.Join(",", message.To.OfType<MailboxAddress>()
                                 .Select(t => $"{t.Name} <{t.Address}>")
                                 .ToArray())}");

                    // Ccを取得する
                    Debug.WriteLine($"Cc：" +
                        $"{string.Join(",", message.Cc.OfType<MailboxAddress>()
                                 .Select(c => $"{c.Name} <{c.Address}>")
                                 .ToArray())}");

                    // 件名を取得する
                    Debug.WriteLine($"件名：{message.Subject}");

                    // メッセージを取得する
                    Debug.WriteLine($"{message.GetTextBody(MimeKit.Text.TextFormat.Plain)}");
                }
            }
            catch (Exception ex)
            {
                Debug.WriteLine($"Failed receive:{ex}");
            }
        }
    }
}

public class Mail
{
    public string ImapHost { get; set; }

    public int ImapPort { get; set; }

    public string UserName { get; set; }

    public string Password { get; set; }
}

var imap = new MailKit.Net.Imap.ImapClient()

await imap.Inbox.OpenAsync(FolderAccess.ReadOnly);

var uids = await imap.Inbox.SearchAsync(SearchQuery.All);

var query = SearchQuery.SubjectContains("お問い合わせ");
var uids = await imap.Inbox.SearchAsync(query);

var query = SearchQuery.FromContains("@gmail.com");
var uids = await imap.Inbox.SearchAsync(query);

var query = SearchQuery.SubjectContains("お問い合わせ").And(SearchQuery.FromContains("Gmail"));
var uids = await imap.Inbox.SearchAsync(query);

var message = await imap.GetMessageAsync(uid);

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
    }

    private async void Button_Click(object sender, RoutedEventArgs e)
    {

        var mail = new Mail()
        {
            ImapHost = "imap.gmail.com",
            ImapPort = 993,
            UserName = "xxxxxxx",
            Password = "1234567890123456",
        };
        var service = new MailService(mail);

        // メールを受信する場合
        await service.ReceiveMailAsync();
    }
}