In at least one of the Forum topic areas I seem to remember reading about the issues some of our colleagues were having with NuGet and their VS X# projects.
Well, this post is good news to you as it suggests an easy way to get around the NuGet problem until Fabrice sorts out the VS 2017 integration of X# into the IDE.
Lets start with a picture of success - here below is a new XSharp solution/project with the required MVVM Light assemblies used in the Reference section of the SE pane :-
For the moment I will assume that you know how to use NuGet with C#, when the IDE works as Microsoft intended it to. But a couple of images won't go amiss anyhow ;-0)
I opened a new C# solution/project and then used the right click context menu to access the NuGet pages.
Search for MVVMlight (as an example of what you may be looking for).
Install what is found in the search :-
There are more dialog boxes/screens than I show here but they are very simple and straightforward :-
After a bit of this and that (not long) we get a C# new sample SE pane with the assemblies referenced - just like that ...... :-
So now all we need do is ..... YES, you have guessed it, open up the XSharp new solution/project and go to add a new / extra reference - then us the 'Add Reference' dialog to navigate to the correct folder in the C# sample :-
Use the 'packages' folder to find the correct DLLs :-
After a few more little and simple dialogs we see this in the folder called 'net45' :-
Then simply multiple select and click OK. And the whole process takes only a minute or two, depending on your speed and/or experience.
So you can do this now in VS 2017, and for any app and for any new X# project.
I suggest you keep one C# solution for downloading any of the NuGet stuff - and - it is not only DLLs you get in a one-off manner, but the NuGet system will inform you of version updates. You may have to periodically go into the NuGet system/screen, I haven't tested that part as yet.
I chose MVVMlight (MvvmLight) simply because I am about to use it quite soon, in one of my own apps.
I hope this helps a few of you new to VS - its actually much simpler to use than many of you think or believe!