Environment tag dosent work?
If you use .NET CORE 1.0, namespace changes to
"Microsoft.AspNetCore.Mvc.TagHelpers"
It seems you need to add @addTagHelper "*, Microsoft.AspNetCore.Mvc.TagHelpers"
to the file containing the html, or if you follow the setup of a default project add it to _ViewImports.cshtml
.
Also make sure you have added Microsoft.AspNetCore.Mvc.TagHelpers
to your project.json.
I had this issue because I wasn't using app.UseStaticFiles();
in my startup