Hello,
If you have the same problem as me then you see just black text when you open any cshtml file, something like that:
so, nothing highlighted, even css and pure html.
Also, in my case there were no "Add View..." on solution context menu and on controller cation context menu.
Unfortunately what did help me is complete uninstall of the VS 2017 and installing again.
hope it will help you as well.
Thank you
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