Convert EML to XLSM in C# .NET

What is EML file format?

The EML file is a type of email message that includes both the message content and the email header information. It is an extension of the Mime (Multipurpose Internet Mail Extensions) format and is used in most email clients, including Microsoft Outlook and Mozilla Thunderbird. EML files are used to save an email message before it is sent and can also be used to archive emails. The EML file format is an XML-structured file that is used to store the header information, such as sender, recipient, subject line, and date, as well as the message content, such as body text, HTML, images, and attachments. The header information is stored in the header of the file and the content is stored in the body. The file is readable by both humans and computers, and can be opened in a text editor, such as Notepad or TextEdit. EML files are commonly used to transfer emails between different email systems. For example, when an email is sent from one email client to another, the email is usually saved as an EML file and then transferred over the internet. This ensures that the message is delivered properly. The EML file format is also used to store emails in an archive. For example, emails can be archived in an EML file and then later opened and read in any compatible email client. This makes it easy to keep emails organized and backed up. In addition to being used for email messages, the EML file format is also used by some applications to store log files, document files, and other types of files.

What is XLSM file format?

The XLSM file format is an extension of the XLSX file format used for Microsoft Excel workbooks. Similar to XLSX, it is based on the Open XML file format and is associated with the Excel application. The “M” in XLSM stands for “macro-enabled”, indicating that it supports the inclusion of macros.

XLSM files store spreadsheet data, including worksheets, formulas, charts, and other elements commonly found in Excel workbooks. Additionally, XLSM files allow the embedding of VBA (Visual Basic for Applications) macros within the workbook. Macros are scripts written in VBA that automate tasks, perform calculations, and interact with the spreadsheet data.

By including macros in XLSM files, users can create customized functions, automate repetitive tasks, and enhance the functionality of their Excel workbooks. Macros can be written to manipulate data, generate reports, perform complex calculations, or interact with other applications.

When opening an XLSM file, Excel prompts the user to enable or disable macros due to security concerns. Enabling macros allows the embedded VBA code to execute, while disabling macros prevents potential security risks associated with malicious code.

XLSM files provide advanced features and customization options for Excel users who require automation beyond the capabilities of the standard XLSX format. They are commonly used in business environments, financial modeling, data analysis, and other scenarios where complex calculations and automation are necessary.