Can I use a value object a Blazor route?

[MrYossu]

Not strictly, a Vogen question, but I'd be surprised if no Vogen user had come across this before, so thought it would be a good place to ask.

I have a Blazor app, and one page shows the details of a company.

Before adding Vogen to the app, the first line of the component looked like this...

@page $"/company-{{Id:int}}"

The component had a corresponding parameter as follows...

  [Parameter]
  public int Id { get; set; }

That worked fine. I've now installed Vogen, and changed the type of the Id property on the Company model to be a value object...

[ValueObject]
public partial struct CompanyId;

I changed the @page directive on the Blazor component to use this...

@page $"/company-{{Id:CompanyId}}"

...and changed the type of the parameter to match, but this gives a run-time exception...

InvalidOperationException: The constraint reference 'CompanyId' could not be resolved to a type. Register the constraint type with 'Microsoft.AspNetCore.Routing.RouteOptions.ConstraintMap'.

I tried adding the following...

builder.Services.Configure<RouteOptions>(opt => opt.ConstraintMap.Add("CompanyId", typeof(CompanyId)));

...which required me to change the value object to look like this...

[ValueObject]
public partial struct CompanyId : IParameterPolicy;

...but this gave a run-time exception...

InvalidCastException: Unable to cast object of type 'System.String' to type 'VogenPlay.Common.Models.CompanyId'.

My guess is that I've got the wrong thing as the first parameter to Add, but I can't find any explanation as to what this is supposed to be.

Anyone able to help? Thanks

[SteveDunn]

I'm pretty sure it can be used in Blazor. I'm not able to test at the moment, but when I'm back online, I'll give this scenario a try (and add a project to the Samples folder).
Thanks for the question!

[viceroypenguin]

@MrYossu Unfortunately, Vogen ids cannot be used in Blazor routes. This is a Blazor limitation, in that it does not yet respect IParseable<> or any other mechanism for providing a parse function to the route system. This is a limitation I've found in my work with Vogen and Blazor as well.

[MrYossu]

@viceroypenguin I had a suspicion that this might be the answer. Shame, but I guess you can only go so far with this.

I got around it by adding a read-only property to my component and using that in the code...

  [Parameter]
  public int Id { get; set; }

  private CompanyId CompanyId =>
    CompanyId.From(Id);

Thanks for the reply

[MrYossu]

@viceroypenguin Do you know if value objects can be used in Blazor component binding? I'm struggling with this. Do you have any thoughts?