I have an existing ASP.NET 4.6 application that I was successfully editing though VS2017.
We recently updated the site to .NET 4.7 and C# 7. The Microsoft.Net.Compilers and CodeDom packages are installed correctly and the website itself works perfectly! My problem is that Visual Studio does not. It doesn't recognize any directives, nor anything asp.
<%@ Page language="c#" %>
In this case, "Page" is highlighted and the error is "Validation (HTML5): Element 'page' is not supported." The same is true for @Master, @Import, @Control or any other directive inany other file on the site. I also get the "Unrecognized tag prefix or device filter 'asp' errors by the zillions, even though other tagPrefixes defined in web.config are fine.
I am at a loss as to why it would be trying to interpret <%@ %> as HTML instead of a directive. To reiterate, the web app works fine. I can even open up the pages indesign view without generating an error. I can build the site without any issues. Thisonly occurs in source view. I have tried everything I can find. VS2017 has been fully updated to 15.2 and repaired. The ReflectedSchemas and other caches have all been cleaned out and rebuilt...
Any suggestions?