Add methods to TagBuilder to render the tags only

[sebastienros]

I am using a TagBuilder to create tags dynamically in a view. In MVC5 we could render the start and end tags independently with the same tag builder without having to render the content. If the content is part of the razor view it can't be added to the instance of the tag builder as it needs to be set with InnerHtml.

A solution that I'd like would be to add two methods, RenderStartTag() and RenderEndTag().

I have tried to use the TagRenderMode without success, it renders the end tag twice.

@{
    TagBuilder tag = new TagBuilder("article");
    tag.AddCssClass("big");
    tag.TagRenderMode = TagRenderMode.StartTag;
}
@tag

<div>MY CONTENT</div>

@{
    tag.TagRenderMode = TagRenderMode.EndTag;
}
@tag

It results in

</article>
<div>MY CONTENT</div>
</article>

Ideally I could just write:

@{
    TagBuilder tag = new TagBuilder("article");
    tag.AddCssClass("big");
}
@tag.RenderStartTag()

<div>MY CONTENT</div>

@tag.RenderEndTag()

Or with a syntax that would capture the razor output:

@using(TagBuilder tag = new TagBuilder("article")) 
{
    tag.AddCssClass("big");
    <div>MY CONTENT</div>
}

[dougbu]

@sebastienros the problem here is the TagBuilder reuse, specifically changing its TagRenderMode before it has rendered the first time. If you use two TagBuilders, everything would be fine.

[sebastienros]

This is another good reason to expose specific rendering methods, that don't use the TagRenderMode

[Eilon]

@sebastienros - is this something you'd like to send a PR for? If not, we will close this.

[sebastienros]

Then I will, thanks.
Who should I talk to about the design?

[dougbu]

@sebastienros me

[Eilon]

Not sure how much "design" there is to do here, but I like the idea of adding RenderStartTag() and RenderEndTag() that do exactly what they say.

[sebastienros]

Not that easy after talking with @dougbu because of the bufferization.

• We'll expose more methods representing all the available modes. RenderStartTag, RenderSelfClosingTag, RenderBody, RenderEndTag
• These methods will return a local implementation of IHtmlContent

[dougbu]

These methods will return a local implementation of IHtmlContent

… except RenderBody(), that can just return _innerHtml 😈