Polymorphic model binding example not working

[KoditkarVedant]

Polymorphic model binding example given here always returns null result.

var modelTypeValue = bindingContext.ValueProvider.GetValue(modelKindName).FirstValue; in particular should return a value but always returns null.

I've added the binder like this in my startup.cs

services.AddMvc(options =>
{
      options.ModelBinderProviders.Insert(0, new DeviceModelBinderProvider());
}); 

Can anyone help me with this?

---

Document Details

⚠ Do not edit this section. It is required for docs.microsoft.com ➟ GitHub issue linking.

• ID: cfb00531-4ac6-8bf6-9bd8-1eed6446397f
• Version Independent ID: ed418d09-6c33-699a-0d48-9aabc99457be
• Content: Custom Model Binding in ASP.NET Core
• Content Source: aspnetcore/mvc/advanced/custom-model-binding.md
• Product: aspnet-core
• Technology: aspnetcore-mvc
• GitHub Login: @ardalis
• Microsoft Alias: riande

[Rick-Anderson]

Moved to Master issue for Custom Model Binding #16319