17.6 CS0029 Cannot implicitly convert type 'Microsoft.AspNetCore.Components.ElementReference' to '[class name]'

After updating to 17.6, with inherited components we are getting CS0029 Cannot implicitly convert type 'Microsoft.AspNetCore.Components.ElementReference' to '[class name]'

This can be reproduced with the following three components:

BaseButton.razor

@inherits Button
@{
    base.BuildRenderTree(__builder);
}

@code
{
    protected virtual string Text { get; }

    protected RenderFragment TextChildContent
    {
        get
        {
            if (Text == null)
                return null;

            return @<span>@Text</span>;
        }
    }

    protected override void OnInitialized()
    {
        if (Text != null)
            ChildContent = TextChildContent;

        base.OnInitialized();
    }

    public async Task InvokeStateHasChangedAsync(bool disabled)
    {
        Disabled = disabled;

        await InvokeAsync(StateHasChanged);
    }
}

OKButton.razor

@inherits BaseButton
@{
    base.BuildRenderTree(__builder);
}

@code
{
    protected override string Text => "OK";

    protected override void OnInitialized()
    {
        Type     = ButtonType.Primary;
        HtmlType = "submit";

        base.OnInitialized();
    }
}

ButtonTest.razor

<OKButton   @ref = "_object" />
<BaseButton @ref = "_baseButton" />
<OKButton   @ref = "_okButton" /> @*CS0029 compile error*@

@code
{
    object     _object;
    BaseButton _baseButton;
    OKButton   _okButton;
}

<OKButton @ref = "_object" /> and <BaseButton @ref = "_baseButton" /> compile fine, but <OKButton @ref = "_okButton" /> produces the error, so perhaps it’s related to the second level of inheritance.

Download the three razor components here: RazorComponents.zip

In this example, the inherited Button is from AntDesign.

[michaelcsikos]

What an absolute trainwreck. I don’t care if it works in the .NET 8 SDK preview; it worked just fine prior to VS 17.6. We’re using .NET 7 for projects in the real world with paying clients. This is a pretty simple scenario and I can’t understand how a regression like this creeps in.

I’ve said before that Visual Studio updates have become a joke. Two years later and the joke is still on us.

[TheCakeMonster]

I have managed to work around this in my own code; just posting here in case it helps anyone else.

In my scenario the code associated with the component was in a separate file, containing a partial class. I changed the partial class in the component1.razor.cs file to explicitly inherit from the class that was mentioned in the @inherit attribute in the component1.razor file and the problem went away.

If you are completely stuck then this might help.

I’ll add some sample code when I get a moment; I’ve got to go into a meeting now.