using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Windows.Forms; using System.Net; using System.Net.Mail; namespace SendMailCSharp { public partial class Form1 : Form { public Form1() { InitializeComponent(); } private void button1_Click(object sender, EventArgs e) { var fromAddress = new MailAddress("from@gmail.com", "From Name"); var toAddress = new MailAddress("to@example.com", "To Name"); const string fromPassword = "fromPassword"; const string subject = "Subject"; const string body = "Body"; var smtp = new SmtpClient { Host = "smtp.gmail.com", Port = 587, EnableSsl = true, DeliveryMethod = SmtpDeliveryMethod.Network, UseDefaultCredentials = false, Credentials = new NetworkCredential(fromAddress.Address, fromPassword) }; using (var message = new MailMessage(fromAddress, toAddress) { Subject = subject, Body = body }) { string aMsg; try { smtp.Send(message); aMsg = "テストメールを送信しました。"; } catch { aMsg = "テストメールを送信に失敗しました。"; } MessageBox.Show(aMsg); } } } }