My advice would actually be not to go this way because of the complexities. Some of the problems you're going to have to solve with a C# editor are:
- What represents your objects in your C# editor?
- How are you going to get your editor to tell your C++ runtime what to do?
- If you do it over the network you're going to have to have some way of packing up data and sending it over and then unpacking it on the other side.
- If you do it with a C++/CLI you can end up wrapping alot of C++ classes with C++/CLI equivalents leading to duplication of code and a lot of maintenance.
- What do you do if the C++ engine crashes, how does the editor handle this case?
- WPF is not beginner friendly, i personally detested it when i was using it, but this is purely a personal opinion.
- Its more difficult to get fancy editor features like asset previews working, at a later date.
- I've seen projects using this approach get extremely complex.
I'd like to propose that you do what Unreal does which is to write your editor UI in C++ using your rendering API to draw it. This has the following good and bad points:
+ There is no duplication of classes for the interop with C#.
+ There is no need for network communication or data packing and unpacking.
+ If it crashes you're in the same process and can therefore debug it more easily. With the C# approach this can be trickier depending on your setup.
+ No WPF, again personal.
+ You can do all of the fancy editing features you want because you're in full control.
+ It can still be complex but in my experience less so.
- Alot of work to write a custom UI solution, will take a little while to see the fruits of your labor. Its totally worth it IMO though.
- Don't have the reliability of established frameworks like .net.
- If it crashes the whole editor goes down but generally you shouldnt be crashing anyways.
So in summary I'm personally not an advocate of wrapping C++ libraries for use in C# unless absolutely necessary and having worked on several different types of editors that have done it in various ways, the most flexible and exciting approach is as i've recommended here but it is quite a bit of work up front.
Hope that gives you some ideas,