Blazor wasm: RZ9991 build error when updating from 7.0.203 to 7.0.302 sdk

[almightyju]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

When using a control WrappedSwitch that extends another control WrappedCheckbox which then extends InputBase<bool> using the WrappedSwitch with @bind-Value="SomeBool" will compile ok in 7.0.203 but in 7.0.302 results in:

error RZ9991: The attribute names could not be inferred from bind attribute 'bind-Value'. Bind attributes should be of the form 'bind' or 'bind-value' along with their corresponding optional parameters like 'bind-value:event', 'bind:format' etc.

Expected Behavior

The code should compile in both sdk vesions

Steps To Reproduce

Create a new blazor wasm project from a template.

In the shared folder create the following controls:

WrappedCheckbox

@using System.Diagnostics.CodeAnalysis
@inherits InputBase<bool>

<div class="form-check @WrapperDivCSS">
	<input id="@Id" class="form-check-input" type="checkbox" @bind="CurrentValue" @attributes="AdditionalAttributes" />
	<label class="form-check-label" for="@Id">@Label</label>
</div>

@code {
	[Parameter] public string? Label { get; set; }
	[Parameter] public string? WrapperDivCSS { get; set; }

	string Id { get; init; } = Guid.NewGuid().ToString();

	protected override bool TryParseValueFromString(string? value, out bool result, [NotNullWhen(false)] out string? validationErrorMessage)
	{
		bool parsed = bool.TryParse(value, out result);
		validationErrorMessage = parsed ? null : $"Failed to parse {value} as a boolean";
		return parsed;
	}
}

WrappedSwitch

@inherits WrappedCheckbox

<WrappedCheckbox Label="@Label" Value="@Value" ValueChanged="@ValueChanged" ValueExpression="@ValueExpression"
                 DisplayName="@DisplayName" WrapperDivCSS="form-switch" AdditionalAttributes="@AdditionalAttributes" />

@code {
}

Then replace the Index page with:

@page "/"

<PageTitle>Index</PageTitle>

<EditForm Model="EditItem">
	<WrappedSwitch Label="My Switch" @bind-Value="EditItem.MyProp"/>
</EditForm>

@code {
	public class EditModel
	{
		public bool MyProp { get; set; }
	}
	public EditModel EditItem { get; set; } = new();
}

Compile using both sdks and 203 will succeed while 302 fails

Exceptions (if any)

No response

.NET Version

No response

Anything else?

No response

[ScarletKuro]

Probably related #8718

[fretje]

I have the same issue (a component that's derived from a base component and the property to @bind to is in the base component).

This is blocking for us. I have to pin the sdk version to 7.0.203 to be able to build.

It's very strange behavior to say the least... the compiler is complaining, but the error is not visible in the code (with the red squiggle) like it normally is.

When I use @bind-Value (where the Value and ValueChanged properties are defined in the base class) like this;

<MyComponent @bind-Value="_value" />

I get:

error RZ9991: The attribute names could not be inferred from bind attribute 'bind-Value'. Bind attributes should be of the form 'bind' or 'bind-value' along with their corresponding optional parameters like 'bind-value:event', 'bind:format' etc.

And when I remove the @bind-Value:

<MyComponent />

I get another error:

error RZ10012: Found markup element with unexpected name 'MyComponent'. If this is intended to be a component, add a @using directive for its namespace.

I have tried adding a @using statement, or fully qualifying the namespace, but nothing helps.

[ArgoZhang]

same issue. it work fine use 7.0.203

[jjonescz]

Sorry you're hitting this. Seems like a regression fixed by #8614 but not yet in .NET 7. To confirm, try if your code works with .NET 8 SDK preview.

[fretje]

I found a way around it, by reading some of the other issues that have been posted about this.

I simply had to derive the "most" base component in the hierarchy chain from ComponentBase explicitly (in a the .razor.cs file), and this fixed the errors for us.