Set Default/Null Value with Select TagHelper

Question

In asp.net mvc you can use:

@Html.DropDownListFor(model => model.Category, ViewBag.Category as IEnumerable<SelectListItem>, "-- SELECT --", new { @class = "form-control" })

Using asp.net 5, how do I include the default or null value (-- SELECT --) in a taghelper:

<select asp-for="Category" asp-items="@ViewBag.Category"  class="form-control"></select>

Answer 1

You can just insert an option item inside the select:

<select asp-for="Category" asp-items="@ViewBag.Category"  class="form-control">
    <option disabled selected>--- SELECT ---</option>
</select>

The disabled keyword in the code above means that the "--- SELECT ---" row cannot be picked again once a choice has been selected in the list. If you want the user to be able to blank the selection again (i.e. if it's bound to a nullable field) then just omit disabled.