C# - Send HTML Email with Embedded Images

The following c# example codes demonstrate how to send HTML email with embedded images.

To attach an embedded images to email, you should add an attachment to email at first. Then you should assign an unique identifier(contentid) to this attachment. Finally, you need to replace the <img src="your file name" /> to <img src="cid:yourcontentid" />.

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.

C# - Send HTML Email with Embedded Images - Example

The following example codes demonstrate sending email with embedded images. 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.

using System;
using System.Collections.Generic;
using System.Text;

// Add EASendMail namespace
using EASendMail;

namespace mysendemail
{
    class Program
    {
        static void Main(string[] args)
        {
            SmtpMail oMail = new SmtpMail("TryIt");
            SmtpClient oSmtp = new SmtpClient();

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

            // Set recipient email address, please change it to yours
            oMail.To = "support@emailarchitect.net";

            // Set email subject
            oMail.Subject = "test html email with attachment from c#";

            // Your SMTP server address
            SmtpServer oServer = new 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;

            try
            {
                // Add image attachment from local disk
                Attachment oAttachment = oMail.AddAttachment("d:\\test.gif");

                // Specifies the attachment as an embedded image
                // contentid can be any string.
                string contentID = "test001@host";
                oAttachment.ContentID = contentID;
                oMail.HtmlBody = "<html><body>this is a <img src=\"cid:"
                    + contentID + "\"> embedded image.</body></html>";

                Console.WriteLine("start to send email with embedded image...");
                oSmtp.SendMail(oServer, oMail);
                Console.WriteLine("email was sent successfully!");
            }
            catch (Exception ep)
            {
                Console.WriteLine("failed to send email with the following error:");
                Console.WriteLine(ep.Message);
            }
        }
    }
}

To attach embedded images/pictures, SmtpMail.ImportHtmlBody and SmtpMail.ImportHtml methods are strongly recommended. With these methods, you don’t have to specify the ContentID manually. The html source/file html body can be imported to email with embedded pictures automatically.

You can also refer to the htmlmail.* samples in EASendMail Installer. Those samples demonstrate how to build a HTML email editor and send HTML email with attachment or embedded images/pictures.

c# html editor

Appendix

Comments

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