Important

Detached Mapper is in maintenance mode.

It's been a long journey since I got tired of mapping and attaching entities by hand and started learning and writing this code. AI has changed how we program in a very short time: most of us no longer worry about mapping, and I doubt many still reach for this library.

Thank you to everyone who wrote in, reported, contributed and donated: you made this journey interesting and rewarding.

One last release, 11.0.0, will ship when EF Core 11 does (November 2026).

If deterministic mapping, messaging and frameworks still interest you, NSail is the next iteration of everything learned here. Its mapper keeps Detached's graph semantics, rebuilt as a compile-time source generator: no reflection, AOT-compatible, build errors instead of runtime surprises. It is not a drop-in replacement: it is part of the NSail Stack. Anyone who wants to join is welcome!

Thanks for everything. Leonardo

Maps Dtos directly to entities already attached to a DbContext

Solves disconnected entities, partial updates and automapping in a single step

Getting started

Check getting started on the new wiki.

Play in .Net Fiddle

A couple of examples to check library capabilities without installing anything.

• Attach graph of anonymous objects
• Import json graph

Issues and feedback

Please use GitHub Issues tab to report anything you find using the library. All feedback is welcome, I'll try to prioritize and fix everything, but I have limited personal time to work on this.

Changes & Breaking Changes

Please take a look at the new list here.

PR your test!

Fork the project and send me a PR with your tests in the Contrib folder and I will include them so that in the future I won't break your solution with changes. And I'll make it pass if they are broken because of an issue. I know the library needs ton more of tests, but resources here are limited. Sorry and thanks for your contribution!

Urgent issues

If something is blocking your project and you need help asap, contact me at my e-mail.

Donations & Support

If you like my work and want to Buy me a Coffee, that would be awesome! (mail me if that doesn't work for you)

Thanks for your feedback and kindly donations!:

• @RobertInDotNET and the entire team of SysTec Computer GmbH (https://www.systec-computer.de/)
• @traiannemes
• @MichaelM223
• @heyadamhey

And thanks to all the people who gave it a try and reported issues! Thanks for your help and patience.

Related tools

Other packages built to provide features to the mapper:

• Runtime Types
• Patch Types