Button TagHelper for formaction

[yishaigalatzer]

Initial suggestion - Need to fill in more details,

Scenario

A form with multiple buttons, that needs to go do different actions based on what was clicked.

<form ...>
    ...
    <button type="submit" formaction="/Album/Edit">Edit</button>
    <button type="submit" formaction="/Album/Delete">Delete</button>
</form>

A Tag helper look like

<button asp-action="Edit" asp-controller="Album" />

And Generate

<button formaction="Album/Edit" />

Similarly we can make these attributes also work on the input tag helper, when type is submit.

[yishaigalatzer]

CC @DamianEdwards @NTaylorMullen @dougbu

[Eilon]

@DamianEdwards @danroth27 there seems to be some renewed interest in this (see #5034). Thoughts?

[DamianEdwards]

Seems very simple to add and very useful. SOLD! Fit in 1.1?

[Eilon]

Marking as up-for-grabs in case anyone wants to try their hand at it.

[ctyar]

Is this design final? if so I can give it a try

[Eilon]

@ctyar well I'm not sure I'd call this exactly a design, it's more like some random thoughts people had 😄

But... it probably is fairly straightforward. We'd presumably want to do exactly what we do for stuff like the <form> tag and <a> tag as far as the tag helper attributes it should have, and the behavior it should have if there's an existing explicit formaction attribute defined on the tag.

If you want to take a crack at it, let us know, and send a PR when you're ready.

[ctyar]

@Eilon yeah I found those two, I'm already on it

[Eilon]

@ctyar sounds great, looking forward to see the PR! Thanks!