Unfortunately I don't figure out any workaround except rewriting by yourself the webmap serialization but it's not that easy.Maybe, instead of subclassing the GraphicsLayer, you might add the new functionalities you need by using attached properties.But it's just my 2cts because I have idea about your need.
You are right, custom layers inheriting from GraphicsLayer can't be printed.We'll try enhancing it in a future version.Thanks for reporting that.
Signed in members can post, follow updates, and more. New here? Register a free account.
Find useful guides, FAQs, and documents to help you navigate and make the most of Esri Community.