Custom TagHelper does not work in a ASP.NET Web Project (.Net 5)

Question

I have a custom TagHelper like described in the Docs: A minimal Tag Helper

using Microsoft.AspNetCore.Razor.TagHelpers;

namespace MyTagHelpers.TagHelpers
{
    public class EmailTagHelper : TagHelper
    {
        public override void Process(TagHelperContext context, TagHelperOutput output)
        {
            output.TagName = "a";    // Replaces <email> with <a> tag
        }
    }
}

I add my EmailTagHelper in _ViewImports.cshtml:

@addTagHelper *, MyTagHelpers

And use it on the Razor Page

<email></email>

But it does not work.

Answer 1

My Project has Assembly Name set to MyProject.

File MyProject.csproj

 <PropertyGroup>
        <AssemblyName>MyProject</AssemblyName>
 </PropertyGroup>

So, the generated assembly will have file name MyProject.dll

To make my EmailTagHelper work I need to add it with the right Assembly Name:

@addTagHelper *, MyProject

It works, despite the parent namespace of my EmailTagHelper is still the same MyTagHelpers.