InputText and other input components do not use SetUpdatesAttributeName() for two-way binding

[hakenr]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Hi @SteveSandersonMS,
is there any reason why the InputText implementation (and implementation of other input components) do not use the SetUpdatesAttributeName("value") method when it replicates the <input @bind-value="..." /> in BuildRenderTree()?

The changes in DOM get not synchronized to the .NET model then.

As a result when someone wants to derive his own component from InputText e.g. to apply some text formatting and you enter the same text input twice, the first callback causes the UI to replace the value with the formatted value but the second callback leaves the input intact as it does not detect any change in the .NET model to be synchronized to DOM (no matter you call the StateHasChanged() or not).

Expected Behavior

.NET model of InputText and other input components reflect DOM changes (two-way binding) from their underlying input elements.

Steps To Reproduce

public class MyInputText : InputText
{
	protected override bool TryParseValueFromString(string? value, out string? result, [NotNullWhen(false)] out string? validationErrorMessage)
	{
		if (value == "24h")
		{
			result = "24:00:00";
		}
		else
		{
			result = value;
		}
		validationErrorMessage = null;
		return true;
	}
}

<EditForm Model="model">
    <MyInputText @bind-Value="@model.Value" />
</EditForm>
@model.Value

@code
{
    private Model model = new Model();
    private class Model
    {
        public string Value { get; set; }
    }
}

This fixes the issue:

public class MyInputText : InputText
{
	protected override bool TryParseValueFromString(string? value, out string? result, [NotNullWhen(false)] out string? validationErrorMessage)
	{
		if (value == "24h")
		{
			result = "24:00:00";
		}
		else
		{
			result = value;
		}
		validationErrorMessage = null;
		return true;
	}

	protected override void BuildRenderTree(RenderTreeBuilder builder)
	{
		builder.OpenElement(0, "input");
		builder.AddMultipleAttributes(1, base.AdditionalAttributes);
		builder.AddAttribute(2, "class", base.CssClass);
		builder.AddAttribute(3, "value", BindConverter.FormatValue(base.CurrentValue));
		builder.AddAttribute(4, "onchange", EventCallback.Factory.CreateBinder<string>((object)this, (Action<string>)delegate (string? __value)
		{
			base.CurrentValueAsString = __value;
		}, base.CurrentValueAsString, (CultureInfo?)null));
		builder.SetUpdatesAttributeName("value");              // <-------- THIS FIXES THE ISSUE
		builder.CloseElement();
	}
}

Exceptions (if any)

No response

.NET Version

6.0.101

Anything else?

If it helps, I can prepare a PR for this.

Related issue #17281

[SteveSandersonMS]

@hakenr Yes, I think you're right. Thanks for providing such a clear issue description and for checking into the solution.

If you are willing to provide a PR for this (along with some E2E test cases showing that it makes a difference), I'd be happy to work with you to get it merged soon.

[ghost]

We've moved this issue to the Backlog milestone. This means that it is not going to be worked on for the coming release. We will reassess the backlog following the current release and consider this item at that time. To learn more about our issue management process and to have better expectation regarding different types of issues you can read our Triage Process.

[SteveSandersonMS]

Fixed in #46434