<option value=""> incorrectly omits value attribute

Bug

<option value="">[Select]</option> becomes <option>[Select]</option> on the client thus eliminating the ability to select "nothing" as a value in a drop down.

To Reproduce

<div><input id="tbx" value="@MyValue"  /></div>
<div>
    <select id="ddlAdm1" @onchange="@OnMyValChange" value="@MyValue">
        <option value="">[Select]</option>
        <option value="1">One</option>
        <option value="2">Two</option>
    </select>
</div>

@code {
    [Parameter] public string MyValue { get; set; }

    protected void OnMyValChange(ChangeEventArgs e)
    {
        MyValue = e.Value.ToString();
    }
}

Produces

<div><input id="tbx"></div><!--!-->
    <div>
        <!--!-->
        <select id="ddlTest">
            <!--!-->
            <option>[Select]</option><!--!-->
            <option value="1">One</option><!--!-->
            <option value="2">Two</option><!--!-->
        </select><!--!-->
    </div>

This causes selecting the first line to put “[Select]” in the “tbx” input box.

Version Info

.NET Core SDK (reflecting any global.json): Version: 3.1.100 Commit: cd82f021f4

Runtime Environment: OS Name: Windows OS Version: 6.3.9600 OS Platform: Windows RID: win81-x64 Base Path: C:\Program Files\dotnet\sdk\3.1.100\

Host (useful for support): Version: 3.1.0 Commit: 65f04fb6db

Visual Studio 2019

[SteveSandersonMS]

Thanks very much @jonbrauer for reporting this and for providing such a clear repro.

This is a bug and will be fixed in https://github.com/aspnet/AspNetCore/pull/17838. In the meantime, the workaround I’d recommend is to have a different value (other than an empty string) to represent “no selection”, and set that value as the initial value for your bound model property.

[appsupport-gc]

GREAT! Thanks so much!

From: Steve Sanderson [e-mail] Reply-To: aspnet/AspNetCore [e-mail] Date: Thursday, December 12, 2019 at 1:54 PM To: aspnet/AspNetCore [e-mail] Cc: AppSupport [e-mail], Mention [e-mail] Subject: Re: [aspnet/AspNetCore] <option value=""> incorrectly omits value attribute (#17735)

Thanks very much @jonbrauerhttps://github.com/jonbrauer for reporting this and for providing such a clear repro.

This is a bug and will be fixed in #17838https://github.com/aspnet/AspNetCore/pull/17838. In the meantime, the workaround I’d recommend is to have a different value (other than an empty string) to represent “no selection”, and set that value as the initial value for your bound model property.

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