如何验证是否发送电子邮件

Question

这是我的代码。我用它来验证电子邮件地址。

using System;
using System.Web;
using System.ComponentModel.DataAnnotations;
using System.Web.Mvc;
using System.Threading.Tasks;
using System.Collections.Generic;
using System.Data;
using System.Data.Entity;
using System.Linq;
using System.Net;
using Vishwaprani.ContextClass;
using Vishwaprani.Models;
using System.Net.Mail;
using System.Threading;
namespace Vishwaprani.CustomValidator
{
    public class EmailAddresValidationAttribute : ValidationAttribute
    {
        protected override ValidationResult IsValid(object value, ValidationContext validationContext)
        {
            if (value != null)
            {
                string mailadress = Convert.ToString(value);
                MailMessage email = new MailMessage(new MailAddress("emailvalidation123456@gmail.com", "Email validation"), new MailAddress(mailadress, "Validating email address"));
                email.Subject = "email validation";
                   email.Body = @"Test for validation";
                 var client = new SmtpClient("smtp.gmail.com") ;
                client.Port=587;
                client.EnableSsl=true;
                client.Credentials = new System.Net.NetworkCredential("emailvalidation123456", "U50h2#AP2XR@");
                try
                {
                     client.Send(email);
                }
                 catch(SmtpFailedRecipientException ex)
                {
                     if(ex.StatusCode==SmtpStatusCode.GeneralFailure||ex.StatusCode==SmtpStatusCode.LocalErrorInProcessing||ex.StatusCode==SmtpStatusCode.ServiceNotAvailable||ex.StatusCode==SmtpStatusCode.TransactionFailed)
                     {
                         Thread.Sleep(5000);
                         try
                         {
                             client.Send(email);
                         }
                         catch(SmtpFailedRecipientException exc)
                         {
                             if (exc.StatusCode == SmtpStatusCode.GeneralFailure || exc.StatusCode == SmtpStatusCode.LocalErrorInProcessing || exc.StatusCode == SmtpStatusCode.ServiceNotAvailable || exc.StatusCode == SmtpStatusCode.TransactionFailed)
                             {
                                 return new ValidationResult("There is a problem with your email address that can not be resolved. Please check it and try again later or enter another one.");
                             }
                         }
                     }
                     else if(ex.StatusCode==SmtpStatusCode.ExceededStorageAllocation||ex.StatusCode==SmtpStatusCode.InsufficientStorage)
                     {
                         return new ValidationResult("There is a storage issue with the email account. Please resolve that.");
                     }
                     else if(ex.StatusCode==SmtpStatusCode.MailboxBusy)
                     {
                         Thread.Sleep(5000);
                         try
                         {
                             client.Send(email);
                         }
                         catch(SmtpFailedRecipientException exct)
                         {
                             if (exct.StatusCode == SmtpStatusCode.MailboxBusy)
                             {
                                 return new ValidationResult("Mail box is busy two times try again later.");
                             }
                         }
                     }
                     else if(ex.StatusCode==SmtpStatusCode.MailboxUnavailable)
                     {
                         return new ValidationResult("Mail box is unavailable.");
                     }
                     else
                     {
                         return new ValidationResult("There is an error with the email address you provided. Please check it.");
                     }
                }
                return ValidationResult.Success;
             }
            else return null;
        }
    }
}

问题是，当我将邮件发送到错误的电子邮件地址时，代码不会抛出SmtpFailedRecipientException并转到validationresult。成功。无论如何，我对这个SmtpClient的东西很新。有谁知道如何解决这个问题？ 。这是我用于验证的错误电子邮件地址：

dffhgjwghxjgwjhxg@gjh3egxejh.comedkjk. 

正如你所看到的那样，人们根本不可能存在那种电子邮件地址。

证明（与我的一起检查）：

Answer 1

try 
{
    address = new MailAddress("emailvalidation123456@gmail.com", "Email validation").Address;
} 
catch(FormatException) {
    //Invalid email address
}

MailAdress.Address属性在您尝试获取时抛出FormatException。

修改

在发送电子邮件之前，您无法验证电子邮件地址是否存在。您可以使用SmtpClient.SendCompleted Event查看投放状态。

client.SendCompleted += new 
            SendCompletedEventHandler(SendCompletedCallback);


private static void SendCompletedCallback(object sender, AsyncCompletedEventArgs e)
{
    // Get the unique identifier for this asynchronous operation.
    String token = (string)e.UserState;

    if (e.Cancelled)
    {
        Console.WriteLine("[{0}] Send canceled.", token);
    }
    if (e.Error != null)
    {
        Console.WriteLine("[{0}] {1}", token, e.Error.ToString());
    }
    else
    {
        Console.WriteLine("Message sent.");
    }
    mailSent = true;
}