How to use C# 6 with Web Site project type?

Question

Updated an existing Web Site project type Visual Studio 2015, I changed the Framework to 4.6.

I then expected to have all those new features available in my

Answer 1

Possible solutions, taken from the comments on ScottGu's blog posting (search for "8026" on the page):

Solution suggestion 1 (David Taylor)

Add these RTM code dom elements to web.config:

Then add the Roslyn and Microsoft.CodeDom.Providers.*.dll stuff into your BIN directory.

It is easy enough to setup, but just was strange to me that the default template wasn't set up for it if you selected .NET 4.6 when creating a new "Web Site" in VS 2015 RTM.

Solution suggestion 2 (Martin)

Further to David Taylor's comment above, it looks like the system.codedom settings are correct when a Web App is created with the TargetFramework as the default v4.5.2. Changing the TargetFramework to v4.6 appears to modify the compiler settings for CSharp, in a way that causes an issue.

My workarounds was as follows:

1. File/New/ASP.NET Web Application
2. Select "Web API" template from ASP.NET 4.5.2 Templates
3. Take a copy of the system.codedom element (and its contents) in web.config
4. Using Properties/TargetFramework, set the Target Framework to 4.6
5. Replace the modified system.codedom element in web.config with the copy taken prior to changing TargetFramework
6. Hit F5

Home Page should load as expected.

For info, the system.codedom contents immediately after changing TargetFramework to v4.6. was as follows (note use of the Type "Microsoft.CSharp.CSharpCodeProvider"):