试试这个

public static bool Send(string receiverEmail, string ReceiverName, string subject, string body)
{
        MailMessage mailMessage = new MailMessage();
        MailAddress mailAddress = new MailAddress("abc@gmail.com", "Sender Name"); // abc@gmail.com = input Sender Email Address 
        mailMessage.From = mailAddress;
        mailAddress = new MailAddress(receiverEmail, ReceiverName);
        mailMessage.To.Add(mailAddress);
        mailMessage.Subject = subject;
        mailMessage.Body = body;
        mailMessage.IsBodyHtml = true;

        SmtpClient mailSender = new SmtpClient("smtp.gmail.com", 587)
        {
            EnableSsl = true,
            UseDefaultCredentials = false,
            DeliveryMethod = System.Net.Mail.SmtpDeliveryMethod.Network,
            Credentials = new NetworkCredential("abc@gmail.com", "pass")   // abc@gmail.com = input sender email address  
                                                                           //pass = sender email password
        };

        try
        {
            mailSender.Send(mailMessage);
            return true;
        }
        catch (SmtpFailedRecipientException ex)
        { 
          // Write the exception to a Log file.
        }
        catch (SmtpException ex)
        { 
           // Write the exception to a Log file.
        }
        finally
        {
            mailSender = null;
            mailMessage.Dispose();
        }
        return false;
}

在谷歌更新后，这是使用c#或。net发送电子邮件的有效方法。

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

namespace EmailApp
{
    internal class Program
    {
        public static void Main(string[] args)
        {
            String SendMailFrom = "Sender Email";
            String SendMailTo = "Reciever Email";
            String SendMailSubject = "Email Subject";
            String SendMailBody = "Email Body";

            try
            {
                SmtpClient SmtpServer = new SmtpClient("smtp.gmail.com",587);
                SmtpServer.DeliveryMethod = SmtpDeliveryMethod.Network;
                MailMessage email = new MailMessage();
                // START
                email.From = new MailAddress(SendMailFrom);
                email.To.Add(SendMailTo);
                email.CC.Add(SendMailFrom);
                email.Subject = SendMailSubject;
                email.Body = SendMailBody;
                //END
                SmtpServer.Timeout = 5000;
                SmtpServer.EnableSsl = true;
                SmtpServer.UseDefaultCredentials = false;
                SmtpServer.Credentials = new NetworkCredential(SendMailFrom, "Google App Password");
                SmtpServer.Send(email);

                Console.WriteLine("Email Successfully Sent");
                Console.ReadKey();
            }
            catch (Exception ex)
            {
                Console.WriteLine(ex.ToString());
                Console.ReadKey();
            }

        }
    }
}

要创建应用程序密码，您可以按照这篇文章: https://www.techaeblogs.live/2022/06/how-to-send-email-using-gmail.html

从另一个答案复制，上述方法工作，但gmail总是替换“从”和“回复”电子邮件与实际发送gmail帐户。然而，显然有一种方法:

http://karmic-development.blogspot.in/2013/10/send-email-from-aspnet-using-gmail-as.html

“3。在帐户选项卡，点击链接“添加另一个电子邮件地址你自己的”，然后验证它

或者可能是这个

更新3:读者德里克·贝内特说:“解决办法是进入你的gmail设置:账户，并“默认”一个gmail账户以外的账户。这将导致gmail用默认帐户的电子邮件地址重写From字段。”

来源:在ASP发送电子邮件。净c#

下面是一个使用c#发送邮件的示例工作代码，在下面的例子中，我使用谷歌的smtp服务器。

代码是相当不言自明的，替换电子邮件和密码与您的电子邮件和密码值。

public void SendEmail(string address, string subject, string message)
{
    string email = "yrshaikh.mail@gmail.com";
    string password = "put-your-GMAIL-password-here";

    var loginInfo = new NetworkCredential(email, password);
    var msg = new MailMessage();
    var smtpClient = new SmtpClient("smtp.gmail.com", 587);

    msg.From = new MailAddress(email);
    msg.To.Add(new MailAddress(address));
    msg.Subject = subject;
    msg.Body = message;
    msg.IsBodyHtml = true;

    smtpClient.EnableSsl = true;
    smtpClient.UseDefaultCredentials = false;
    smtpClient.Credentials = loginInfo;
    smtpClient.Send(msg);
}

这是不再支持，如果你正在尝试这样做现在。

https://support.google.com/accounts/answer/6010255?hl=en&visit_id=637960864118404117-800836189&p=less-secure-apps&rd=1#zippy=

谷歌可能会阻止一些不使用现代安全标准的应用程序或设备的登录尝试。由于这些应用程序和设备更容易被侵入，屏蔽它们有助于让你的账户更安全。

不支持最新安全标准的应用程序包括:

iOS 6或以下版本的iPhone或iPad上的邮件应用程序 8.1版本之前Windows手机上的邮件应用程序 一些桌面邮件客户端，如Microsoft Outlook和Mozilla Thunderbird

因此，您必须在您的谷歌帐户中启用“较少安全登录”。

登录谷歌账号后，进入:

https://myaccount.google.com/lesssecureapps 或 https://www.google.com/settings/security/lesssecureapps

在c#中，你可以使用以下代码:

using (MailMessage mail = new MailMessage())
{
    mail.From = new MailAddress("email@gmail.com");
    mail.To.Add("somebody@domain.com");
    mail.Subject = "Hello World";
    mail.Body = "<h1>Hello</h1>";
    mail.IsBodyHtml = true;
    mail.Attachments.Add(new Attachment("C:\\file.zip"));

    using (SmtpClient smtp = new SmtpClient("smtp.gmail.com", 587))
    {
        smtp.Credentials = new NetworkCredential("email@gmail.com", "password");
        smtp.EnableSsl = true;
        smtp.Send(mail);
    }
}