title: Why do I get "Visual Basic 12 does not support multiline string literals" in Visual Studio 2017?
body: <p>I have an old ASP.NET Web Forms web site (VB) that I created years ago.</p>
  
  <p>I am currently working with Visual Studio 2017, my web site is targeting the .NET 4.5 framework and everything works correctly.</p>
  
  <p>Except when I try to use multi-line string literals, then I get this message: </p>
  
  <p>"Visual Basic 12.0 does not support multi-line string literals."</p>
  
  <p>But I know VS 2017 comes with VB 15. And if I create a new empty web site (VB) project, then I can use multi-line strings with no problems. So I guess I have to update a setting somewhere?</p>
  
  <p>Please help. Thanks.</p>