Create MIME messages using C#

When sending an email, you may need to send multimedia content such as images, audio, and video. This is where MIME (Multipurpose Internet Mail Extensions) messages come into play. In this article, we will explore how to create EML messages programmatically in C#. By the end of the article, you will have an understanding of how to create MIME messages, add images to the HTML content of the email and save email to EML format.

.NET API to Create MIME Messages

Before you create your first MIME message, the first step is to install Aspose.Email for .NET in your project. It is a powerful library for C# developers that provides a comprehensive set of tools for working with email messages, including the ability to create MIME messages programmatically. The library helps developers easily manipulate various aspects of MIME messages, such as attachment, body, header, encoding, and more. You can either install the library via NuGet or download its DLL.

PM> Install-Package Aspose.Email

Create an EML File from Scratch

Since your API has been installed, it’s time to create your first eml from scratch. One of the simplest ways to do it is to use the MailMessage class from Aspose.Email. The MailMessage class allows you to create an email message object with various properties and methods that let you set the sender, recipients, subject, body, attachments, headers, and other details of your email.

The following steps and a code snippet will help you create an EML from scratch:

  • Create a new MailMessage object using the default constructor.
  • Set the properties of the MailMessage object according to your needs.
  • Save the MailMessage object to an EML file using the Save method.

The Save method of the MailMessageclass takes two parameters: the file path and the save options. The save options specify the format of the output file.

Add an Image to the HTML Content

To perform this function, you need to embed the image in the html body. You can use the “img” tag to do this.

The following code snippet shows how to add an image to the HTML body of a message.

  • The HTML body contains an image tag with a source attribute set to cid:image1.
  • The AlternateView class is used to get an alternate view of the message body that contains the embedded image.
  • The LinkedResource class is used to represent the embedded image and its content ID is set to image1.
  • Finally, the alternate view is added to the message alternate views collection.

Create an EML File from an HTML File

One way to do this is to start with an HTML file and convert it to EML. This can be useful if you have an HTML that you want to send as an email message. For this purpose we first need to have the HTML content. Let’s call this file content.html. Here’s an example of it:

<!DOCTYPE html>
<html>
<head>
	<title>My Email</title>
</head>
<body>
	<h1>Hello,</h1>
	<img src="logo.png" alt="Logo">
	<p>This is my first email created form HTML.</p>
</body>
</html>

Also, you must prepare in advance all the images that contain HTML, and specify the correct path to them in the HTML file.

Now, we can easily create a MailMessage by setting the HTML body from the content.html.

  • First, create a new HtmlLoadOptions object.
  • Set a string that contains the path to the images in PathToResources.
  • Set ShouldAddPlainTextView property to true if EML should contain AlternateView with plain text.
  • Create a MailMessage object by loading the HTML file and passing the HtmlLoadOptions object as a parameter.
  • Set additional message properties.
  • Finally, save the MailMessage object to an EML file using the Save method.

Tips for Improving the View of the HTML Message in Outlook

To view your HTML message in Outlook, you need to make sure that its code is compatible with Outlook rendering engine, which is different from most web browsers. Some of the common issues that may affect your HTML email in Outlook are:

  • Outlook does not support some of its tags and CSS properties, such as background images, floats, margins, padding, etc. You may need to use inline styles, tables, or conditional comments to achieve the desired layout and formatting.
  • Outlook may add extra spaces or lines between elements or remove some elements altogether. You may need to use non-breaking spaces, zero-width spaces, or empty table cells to prevent this.
  • Outlook may change the encoding or character set of your HTML file, which may cause some characters to display incorrectly. You may need to specify the encoding and character set in it using a meta tag.

Conclusion

In this blog post, you have learned how to create MIME messages programmatically in C# using Aspose.Email. The step by step tutorial and code samples showed how to create an eml file from scratch and from HTML file, add an image to the HTML content of the email message, and supported all the above mentioned with useful tips on how to improve the view of your HTML message in Outlook.

  • You can explore more about Aspose.Email for .NET and try it for free.
  • You can also check out for more features and functionalities of Aspose.Email in the documentation .
  • Your questions are welcome on our forum.

See Also