Send Email with Multiple Threads(Mass Mail) in Managed C++/CLI¶

#include "stdafx.h"

using namespace System;
using namespace EASendMail;

int main(array<System::String ^> ^args)
{
    array<String^> ^arRcpt = {"test1@adminsystem.com",
        "test2@adminsystem.com",
        "test3@adminsystem.com" };

    int nRcpt = arRcpt->Length;
    array<SmtpMail^> ^arMail = gcnew array<SmtpMail^>(nRcpt);
    array<SmtpClient^> ^arSmtp = gcnew array<SmtpClient^>(nRcpt);
    array<SmtpClientAsyncResult^> ^arResult = gcnew array<SmtpClientAsyncResult^>(nRcpt);

    for (int i = 0; i < nRcpt; i++)
    {
        arMail[i] = gcnew SmtpMail("TryIt");
        arSmtp[i] = gcnew SmtpClient();
    }

    for (int i = 0; i < nRcpt; i++)
    {
        SmtpMail ^oMail = arMail[i];

        // Set sender email address
        oMail->From = "sender@emailarchitect.net";
        // Set recipient email address
        oMail->To = arRcpt[i];

        // Set email subject
        oMail->Subject = "mass email test from Managed C++";
        // Set email body
        oMail->TextBody = "test from Managed C++, this email is sent to " + arRcpt[i];

        // Your SMTP server address
        SmtpServer ^oServer = gcnew SmtpServer("smtp.emailarchitect.net");

        // User and password for ESMTP authentication.
        oServer->User = "test@emailarchitect.net";
        oServer->Password = "testpassword";

        // Most mordern SMTP servers require SSL/TLS connection now.
        // ConnectTryTLS means if server supports SSL/TLS, SSL/TLS will be used automatically.
        oServer->ConnectType = SmtpConnectType::ConnectTryTLS;

        // If your SMTP server uses 587 port
        // oServer->Port = 587;

        // If your SMTP server requires SSL/TLS connection on 25/587/465 port
        // oServer->Port = 25; // 25 or 587 or 465
        // oServer->ConnectType = SmtpConnectType::ConnectSSLAuto;

        SmtpClient ^oSmtp = arSmtp[i];

        // Submit email to BeginSendMail method and return
        // to process another email
        arResult[i] = oSmtp->BeginSendMail(oServer, oMail, nullptr, nullptr );
        Console::WriteLine( String::Format( "Start to send email to {0} ...",
            arRcpt[i] ));
    }

    // all emails were sent by BeginSendMail Method
    // now get result by EndSendMail method

    int nSent = 0;
    while (nSent < nRcpt)
    {
        for (int i = 0; i < nRcpt; i++)
        {
            // this email has been sent
            if (arResult[i] == nullptr)
                continue;
            // wait for specified email ...
            if (!arResult[i]->AsyncWaitHandle->WaitOne(10, false))
            {
                continue;
            }
            try
            {
                // this email is finished, using EndSendMail to get result
                arSmtp[i]->EndSendMail(arResult[i]);
                Console::WriteLine(String::Format("Send email to {0} successfully",
                    arRcpt[i]));
            }
            catch (Exception ^ep)
            {
                Console::WriteLine(
                    String::Format("Failed to send email to {0} with error {1}: ",
                    arRcpt[i], ep->Message));
            }
            // Set this email result to null, then it won't be processed again
            arResult[i] = nullptr;
            nSent++;
        }
    }

    return 0;
}