Managed C++/CLI - Email Queue with EASendMail Service - Database

The following Managed C++/CLI example codes demonstrate how to pick recipients from database and send email using email queue. In the example, we used C:\Program Files\EASendMailService\easendmail_demo.mdb as sample MS Access Database.

SMTP Queue Service

EASendMail Service is a light and fast email delivery service which works with EASendMail SMTP Component to enable your application to send mass emails in background queue service.

Along with its ability to picking recipients from database in background and sending email in specified datetime, it eases your task in developing featured email application such as newsletter application. We strongly recommend you to use EASendMail Service with your ASP.NET/Web Application.

Important

To work with EASendMail Service, please download EASendMail and EASendMail Service at first, and then install both on your machine. If you are using web hosting service and you don’t have permission to install service on that server, EASendMail service is not suitable for you.

With EASendMail email queue feature, you do not have to code for multiple threadings. EASendMail Service can send email in background with multiple threadings automatically. You just need to adjust the maximum worker threads in EASendMail Service Manager to increase the performance. Please click here to learn more detail about EASendMail Service.

Another typical usage scenario is that most newsletter applications get recipient name and address from database. To simplify the task of developer, EASendMail provides a very powerful way to select recipients from database automatically.

C++/CLI email queue + database

Installation

Before you can use the following codes, please download EASendMail SMTP Component and install it on your machine at first. Full sample proejcts are included in this installer.

Install from NuGet

You can also install the run-time assembly by NuGet. Run the following command in the NuGet Package Manager Console:

Install-Package EASendMail

Note

If you install it by NuGet, no sample projects are installed, only .NET assembly is installed.

Add Reference

To use EASendMail SMTP Component in your project, the first step is Add reference of EASendMail to your project. Please create or open your project with Visual Studio, then go to menu -> Project -> Add Reference -> .NET -> Browse..., and select EASendMail{version}.dll from your disk, click Open -> OK, the reference of EASendMail will be added to your project, and you can start to use it to send email in your project.

add reference in c#/vb.net/c++/cli/clr

.NET Assembly

Because EASendMail has separate builds for .Net Framework, please refer to the following table and choose the correct dll.

Separate builds of run-time assembly for .Net Framework 1.1, 2.0, 3.5, 4.0, 4.5 and .Net Compact Framework 2.0, 3.5.

File .NET Framework Version
EASendMail.dll Built with .NET Framework 1.1
It requires .NET Framework 1.1, 2.0, 3.5 or later version.
EASendMail20.dll Built with .NET Framework 2.0
It requires .NET Framework 2.0, 3.5 or later version.
EASendMail35.dll Built with .NET Framework 3.5
It requires .NET Framework 3.5 or later version.
EASendMaill40.dll Built with .NET Framework 4.0
It requires .NET Framework 4.0 or later version.
EASendMaill45.dll Built with .NET Framework 4.5
It requires .NET Framework 4.5 or later version.
EASendMailCF20.dll Built with .NET Compact Framework 2.0
It requires .NET Compact Framework 2.0, 3.5 or later version.
EASendMailCF35.dll Built with .NET Compact Framework 3.5
It requires .NET Compact Framework 3.5 or later version.

MS Access x64 Driver

If your Windows is x64 bit, please download and install MS Access x64 Driver on your server and please change X-Data-Connection like this:

oMail->Headers->ReplaceHeader("X-Data-Connection",
    "Driver={Microsoft Access Driver (*.mdb, *.accdb)}; " +
    "Dbq=c:\\easendmail\\easendmail_demo.mdb;Uid=;Pwd=;");

MS Access Database x64 Driver Download

Microsoft Access Database Engine 2010 Redistributable

C++/CLI - Send Email to Queue Service - Database

The following example codes demonstrate sending email message using email queue + database. In order to run it correctly, please change SMTP server, user, password, sender, recipient value to yours.

Note

To get full sample projects, please download and install EASendMail on your machine.

#include "stdafx.h"

using namespace System;
using namespace EASendMail;

int main(array<System::String ^> ^args)
{
    SmtpMail ^oMail = gcnew SmtpMail("TryIt");
    SmtpClient ^oSmtp = gcnew SmtpClient();

    // Set sender email address, please change it to yours
    oMail->From = "test@emailarchitect.net";

    // Set email subject
    oMail->Subject = "test email from Managed C++/CLI database queue";

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

    // User and password for ESMTP authentication, if your server doesn't require
    // User authentication, please remove the following codes.
    oServer->User = "test@emailarchitect.net";
    oServer->Password = "testpassword";

    // If your smtp server requires SSL connection, please add this line
    // oServer->ConnectType = SmtpConnectType::ConnectSSLAuto;

    // If you want EASendMail service to send the email after 10 minutes,
    // use the following code.
    // oMail->Date = System::DateTime::Now.AddMinutes(10);

    // EASendMail will use the following connection to connect to the database,
    // the syntax is same as ADO connection object.
    oMail->Headers->ReplaceHeader("X-Data-Connection",
        "Driver={Microsoft Access Driver (*.mdb)}; " +
        "Dbq=c:\\easendmail\\easendmail_demo.mdb;Uid=;Pwd=;");

    // EASendMail will select the fields by the following sql statement
    // before sending email,
    // then pick the recipient address from specified field.
    oMail->Headers->ReplaceHeader("X-Sql-Select", "SELECT id, name, address FROM Recipients");

    // pick "name" field as the recipient name and "address" field as
    // the recipient address.
    // you can also use {$var_srecord:fieldname} to pick any field
    // in X-Sql-Select statement and put it to subject, bodytext, then EASendMail will
    // replace it automatially.

    oMail->Headers->ReplaceHeader("To", "\"{$var_srecord:name}\" <{$var_srecord:address}>");
    oMail->Headers->ReplaceHeader("X-Rcpt-To", "{$var_srecord:address}");

    // EASendMail service will execute the following sql statement on
    // every email was sent successfully.
    oMail->Headers->ReplaceHeader("X-Sql-OnSentSuccess",
        "INSERT INTO sentlog (server, email) VALUES('{$var_server}', '{$var_rcptaddr}')");

    // EASendMail service will execute the following sql statement on
    // every email could not be sent.
    oMail->Headers->ReplaceHeader("X-Sql-OnSentError",
        "INSERT INTO errorlog(email, server, errorcode, errordescription)" +
        " VALUES('{$var_rcptaddr}', '{$var_server}', '{$var_errcode}', '{$var_errdesc}')");

    String ^s = "Hi {$var_srecord:name}, \r\n";
    s += "this sample demonstrates how to send email using email queue.\r\n\r\n";
    // {$var_srecord:address} will be replaced by EASendMail automatically.
    s += "Your id in database is {$var_srecord:id}.\r\n\r\n";
    s += "No matter how many recipients there are, EASendMail ";
    s += "service will send the email in background.\r\n\r\n";

    // {$var_srecord:id} {$var_srecord:address} {$var_srecord:name} in
    // body text will
    // be replaced by EASendMail automatically.
    oMail->TextBody = s;
    try
    {
        Console::WriteLine("start to send email to database queue ...");
        oSmtp->SendMailToQueue(oServer, oMail);
        Console::WriteLine("email was sent to queue successfully!");
    }
    catch (Exception ^ep)
    {
        Console::WriteLine("failed to send email with the following error:");
        Console::WriteLine(ep->Message);
    }

    return 0;
}

Appendix

Comments

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