.NET 8 Blazor - Provide Better Developer Feedback for Parameter Deserialization Issues

[sbwalker]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

If you are transitioning from Static rendering to Interactive rendering and you are passing parameters from one component to another, it is critical that the parameters are serializable. If a parameter is not serializable you will get a cryptic run-time error in the browser console which does not provide any indication of the root cause:

DeserializationRepro.razor

<InteractiveComponentWithParameter MissingConstructor="@_missingConstructor" @rendermode="InteractiveServer" />

@code {
    private MissingConstructor _missingConstructor = new MissingConstructor("https://www.microsoft.com/");
}

InteractiveComponentWithParameter.razor

@code {
    [Parameter]
    public MissingConstructor MissingConstructor { get; set; }
}

MissingConstructor.cs

    public class MissingConstructor
    {
        //public MissingConstructor() { }

        public MissingConstructor(string url)
        {
            Uri uri = new Uri(url);
            Host = uri.Host;
        }

        public string Host { get; set; }
    }

Running this code will result in a browser console error:

"Error: The list of component operations is not valid."

Note that to resolve this issue you simply need to uncomment the parameterless constructor in the MissingConstructor.cs class

    public class MissingConstructor
    {
        public MissingConstructor() { }

        public MissingConstructor(string url)
        {
            Uri uri = new Uri(url);
            Host = uri.Host;
        }

        public string Host { get; set; }
    }

Expected Behavior

Provide an error message which is meaningful and helps a developer identify the source of the problem:

ie. "An error occurred deserializing a component parameter"

Even better would be any reference to the actual component name or parameter name causing the issue.

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

8.0.1

Anything else?

No response

[clarity99]

This! It took me most of the day to figure out that serialization is the issue, when my component wasn't working when I set the parameter to IQueryable data source.

[T-mp]

Is there currently a known way to determine the affected class/parameter?
Debugging is not possible because the error only occurs on the server, not when I start it from Visual Studio.