DotNetOpenMail allows you to send email from applications which use Microsoft's .Net development framework, including asp.net, C# and WinForms.

It is a freely available open-source component written in C# that makes it easy to create HTML and plain text email with file attachments without needing the System.Web.Mail library. A programmer can use it to create multipart/alternative, multipart/related and multipart/mixed MIME messages in various character sets and various mime encodings such as quoted-printable, 7bit, 8bit and base64 without needing to know too much about the details.

It is in BETA right now, meaning that the features for the future 1.0 release are included but not widely tested, and the API is not expected to change much.

Buffering problems in Base64 attachments should now be gone. Note that you need to use a BinaryReader instead of a StreamReader to read a binary file in a FileAttachment. Missing ContentIDs have been fixed.

Event delegates were added to SmtpServer to listen to the SMTP conversation for logging and debugging. CaptureSmtpConversation was deprecated. There is a simplistic email address string parser, and although I haven't been able to reproduce the problem, I've added a possible patch for people who are having problems creating a file attachment directly in memory.

An example program, SMTPDebug is now available here. It uses the new logging system to send out raw messages, test SMTP servers, and log the SMTP conversation.

Some patches were contributed for issues with SMTP AUTH for this release. (Thanks to Norbert Bietsch for the patches!)

Special characters such as quotation marks and commas are now properly escaped in email address headers in 0.5.5 beta. There's also a proper error when the "From" name is missing. (Thanks to Kyle Kline for pointing these out!)

Workarounds for the buggy handling of the Russian charset Windows-1251 in the .Net framework have been added to release 0.5.4. A truncated server response is now handled better, and the QP-encoding of question marks now works properly. There are some fixes to the documentation, and the dependency on log4net has been removed from DotNetOpenMail.dll (but not from the unit tests).

The 0.5.3 beta release has one fix to the RFC 2822 Date for non-English systems. There is also a new debugging feature in the SmtpServer class which captures the SMTP Conversation.

The latest beta version has three fixes: two to quoted-printable encoding and one for encoded email addresses. Have a look at the CHANGES.TXT file in the source distribution for more information.

A new version of DotNetOpenMail has been released, and it can be downloaded from here. Changes include the addition of SMTP AUTH (LOGIN) and a fix for the suppressed error for invalid recipients. See the CHANGES.TXT file in the source distribution for more information. This is beta software.

The latest version is 0.5.0b, and it can be found here. This is considered to be beta-quality software. A help file has been included with this release.

News about the releases will be sent to the Announcement Mailing List.