@bind:after is not firing when used with select in Blazor

[imsam67]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

The bind:after is not firing when used in a select in Blazor WASM (Standalone) targeting .NET 9. I understand this was an issue in .NET 7 and was later fixed. I wonder if this is a regression. You can either use the following code or download from public repo at https://github.com/imsam67/blazor-bind-after-issue

Please also note that I tried it .NET 8 and .NET 7. It seems to work only in .NET 7! When I targeted .NET 8, again, I was NOT able to hit the DoSomething() method which should've fired after selecting an option.

<div>
    <select @bind="SelectedState" @bind:after="DoSomething">
        <option value="">Please select one</option>
        <option value="AK">Alaska</option>
        <option value="MT">Montana</option>
        <option value="WY">Wyoming</option>
    </select>
</div>

@code {

    private string SelectedState;

    private async Task DoSomething()
    {
        var userSelected = SelectedState; // Have a break point here but the code doesn't hit it
    }
}

Expected Behavior

When an option is selected, the DoSomething() method should be called.

Steps To Reproduce

Create a Blazor WASM (Standalone) project targeting .NET 9 and use the above code in any page.

Exceptions (if any)

None

.NET Version

9.0.201

Anything else?

No

[javiercn]

@imsam67 thanks for contacting us.

Does the @bind expression get executed at all? (Do you see the value update on the C# side?)

[imsam67]

This appears to be an issue with the debugger. The @bind:after actually fires and the code in it executes but if I use the mouse to make a selection and place a break point inside the method that is supposed to fire with @bind:after, I don't hit the break point even though the code in the method actually executes.

If I use the keyboard to make a selection instead of the mouse, everything works as expected and I hit the break point.

So, this issue seems to be related to the debugger. I found a similar issue here. If I can locate it again, I'll post the link here.

Thank you for your attention to this matter!

[javiercn]

Moving this to razor for them to take a look, it might be an issue with the mappings

[imsam67]

Here's the link to the existing issue I mentioned in my reply the other day: dotnet/aspnetcore#60018

And in case, it maybe useful, here's the issue I'd opened on SO and the discussion I had with other developers that may shed some light to this case: https://stackoverflow.com/questions/79542108/bindafter-is-not-firing-after-selecting-an-option-in-blazor-wasm-app

[phil-allen-msft]

Definitely reads as the same issue, and I believe that the aspnetcore repo is the right place for it to be. dotnet/aspnetcore#60018