Htykuut

I followed a few guides on creating a custom tag helper for ASP Core.

This is my helper:

using Microsoft.AspNetCore.Mvc.ViewFeatures;

using Microsoft.AspNetCore.Razor.TagHelpers;

using System;



namespace ToolControlSystem.TagHelpers

{

    [HtmlTargetElement("description", Attributes = DescriptionAttributeName, TagStructure = TagStructure.NormalOrSelfClosing)]

    public class DescriptionTagHelper : TagHelper

    {

        private const string DescriptionAttributeName = "asp-for";





        [HtmlAttributeName(DescriptionAttributeName)]

        public ModelExpression Model { get; set; }



        public override void Process(TagHelperContext context, TagHelperOutput output)

        {

            base.Process(context, output);



            var description = GetDescription(Model.ModelExplorer);



            output.TagName = "span";

            output.TagMode = TagMode.StartTagAndEndTag;

            output.Content.SetContent(description);

        }



        private string GetDescription(ModelExplorer modelExplorer)

        {

            string description;

            description = modelExplorer.Metadata.Placeholder;



            if (String.IsNullOrWhiteSpace(description))

            {

                description = modelExplorer.Metadata.Description;

            }



            return description;

        }

    }

}

I drop this in _ViewImports.cshtml: @addTagHelper *, ToolConstrolSystem.TagHelpers

Annnndd... nothing. No intellisense, no tag replacing...

Any ideas?

You need to provide only assembly name in the view imports file.

_ViewImports.cshtml: 



@addTagHelper *, ToolConstrolSystem

See Managing Tag Helper scope

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers

@addTagHelper *, AuthoringTagHelpers

The code above uses the wildcard syntax ("*") to specify that all Tag Helpers in the specified assembly (Microsoft.AspNetCore.Mvc.TagHelpers) will be available to every view file in the Views directory or sub-directory.