Different TagHelpers with the same element name, depending on scope

[AlekseyMartynov]

Now we have context.Items (#238) and can compose hierarchies of tag helpers like:

<parent>
    <child attr="value" />
</parent>

It would be nice to be able to map an element name to different tag helpers, depending on a parent tag:

<some-widget>
    <datasource attrs="for" some="widget" />
</some>

<other-widget>
    <datasource something="different" />
</other-widget>

Probably possible in the context of #255: restrict by type name, not by element name.

[dougbu]

@AlekseyMartynov do you have a scenario in mind that would benefit from this type of extension beyond what's described in #255?

[NTaylorMullen]

@AlekseyMartynov @DamianEdwards, @madskristensen and I discussed an extension like this when talking about #255. It's on our road map. At first I was thinking it'd be done as part of #255 but it honestly should be something separate; lets leave this issue open and use it to complete the feature.

Added feature and ready label, will wait for it to be picked up by triage to be assigned a milestone.

[AlekseyMartynov]

@dougbu it's relevant for any tag helper with rich configuration, when you want to use nested tags. Consider:

Case 1 (repeating branded prefix is untidy):

<brandedTag>
    <brandedConfig ... />
</brandedTag>

Case 2 (using simple names globally is conflict-prone):

<brandedTag>
    <config ... />
</brandedTag>

[AlekseyMartynov]

@NTaylorMullen sounds good!

[Eilon]

We decided to add another property to the HtmlTargetElement attribute: string ParentTag { get; set; }

This would restrict a child tag to being that tag helper iff its containing parent is a tag helper with the specified tag name.

[NTaylorMullen]

Hmmmm, so I'm working on this issue and it got me thinking about the required parent interaction. If we have:

<tagHelperA>
  <p>
    <requiresParentA>
    </requiresParentA>
  </p>
</tagHelperA>

And requiresParentA says it has a required parent of tagHelperA. Does the nested requiresParentA tag fulfill its required parent aka have the RequiresParentATagHelper execute on it?

I'm thinking as long as there's a parent (no matter how far up) that fulfills the parent tag then the TagHelper should apply. Thoughts?

[Eilon]

@NTaylorMullen That doesn't sound like it's the feature people want. I would think it has to be immediate parent only.