Enable Tag Helper using @tagHelperPrefix

The @tagHelperPrefix directive allows you to specify a tag prefix string to enable Tag Helper support and to make Tag Helper usage explicit.

For example, you could add the following markup to the Views/_ViewImports.cshtml file:

@tagHelperPrefix cst:

This allows you to enable Tag Helper support by using this prefix (cst). Only those elements using the prefix cst, support the Tag Helpers (Tag Helper-enabled elements have a distinctive font/color).

In the code image below, the <label> element have the Tag Helper prefix (cst), so the Tag Helper is enabled for this element. While the <input> element doesn't have Tag Helper prefix (cst), so Tag Helper is not enabled for this element, this is just a regular HTML element.

The same hierarchy rules that apply to @addTagHelper also apply to @tagHelperPrefix.

References:

• Tag Helpers in ASP.NET Core

Related Post(s):

• Custom Tag Helpers in ASP.NET Core
• Remove Tag Helpers with @removeTagHelper
• Tag Helper scope with _ViewImports file

Tag Helper scope with _ViewImports file

• The _ViewImports.cshtml can be added to any view folder, and the view engine applies the directives from both that file and the Views/_ViewImports.cshtml file.
• The _ViewImports.cshtml file is additive, If you add an empty Views/Home/_ViewImports.cshtml file for the Home views, there would be no change because it will import all tag helpers from Views/_ViewImports.cshtml file.
• If you add new tag helpers in Views/Home/_ViewImports.cshtml file for the Home views, it will import all tag helpers from Views/_ViewImports.cshtml file, also it will import all tag helpers from Views/Home/_ViewImports.cshtml file.
• Any new @addTagHelper directives you add to the Views/Home/_ViewImports.cshtml file (that are not in the default Views/_ViewImports.cshtml file) would expose those Tag Helpers to views only in the Home folder.

References:

• Tag Helpers in ASP.NET Core

Related Post(s):

• Custom Tag Helpers in ASP.NET Core
• Remove Tag Helpers with @removeTagHelper
• Enable Tag Helper using @tagHelperPrefix