TagHelper and non-TagHelper select tags in a form don't work well together.

[NTaylorMullen]

If you have:

<form asp-action="...">
    <select asp-for="...">
        ...
    </select>
    <select>
        <option value="...">...</option>
    </select>
</form>

The <option> tags in the second select will think that they're running under the first <select asp-for="...">. This can be fixed by transitioning the SelectTagHelper to properly use TagHelperContext.Items instead of relying on ViewContext.FormContext.FormData.

[Eilon]

Wow, call that OOPS!

@NTaylorMullen any idea if other tag helpers suffer from cross-talk like this?

[dougbu]

@Eilon this is a to-do item we've had since we added the Items property bag -- which came after the <select> and <option> tag helpers. The problem is a corner case related to lifetime of the information relative to FormContext. And the new <form> tag helper for rendering at the end is the only other one that communicates to children but that one is definitely using the correct mechanism (FormContext). So, no chance of similar issues elsewhere.

[Eilon]

@dougbu thanks, good to know.

[NTaylorMullen]

911dfc5