title: How to use C# 6.0 or 7.0 in an old ASP.NET Website (not Website Project)
body: <p>I have multiple old ASP.NET webforms websites (this is how to create one from scratch):
  <a href="https://i.stack.imgur.com/SzFI5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/SzFI5.png" alt="enter image description here" /></a></p>
  <p>They are not Website Projects.</p>
  <p>ASP.NET Websites seem to be stuck at C# 5. When trying to use features from c# 6 or C# 7 you get an error:
  <a href="https://i.stack.imgur.com/GTNH5.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GTNH5.png" alt="enter image description here" /></a>
  Trying to use the light bulb upgrade option fails:
  <a href="https://i.stack.imgur.com/C7bcK.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/C7bcK.png" alt="enter image description here" /></a>
  Trying any of the other options found at <a href="https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version" rel="nofollow noreferrer">https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/configure-language-version</a> fail too since there is no .csproj file. or an option in the Project Properties page to change the language version.</p>
  <p>Here is what the Build tab looks like on an ASP.NET Website (no Advanced button):
  <a href="https://i.stack.imgur.com/4tyX3.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/4tyX3.png" alt="enter image description here" /></a></p>
  <p>I installed the Microsoft.Net.Compilers NuGet package but that made no difference.</p>
  <p>Any Ideas if this can be done at all in an ASP.NET website?</p>