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Bind to complex object using [FromRoute] in ASP.NET Core 3.x gives null

I have a simple controller which allows a route path constrained by a regex pattern in a 'complex object'. When I try to read the single property from the object it is always null.
The ModelState is showing an errors collection saying:
The ActorId field is required
So it appears to be a model binding issue and not a validation issue.
I feel like I'm missing a pattern in the [HttpGet] block or something.
ActorIdParameter.cs
public sealed class ActorIdParameter
{
[Required]
[RegularExpression(#"^.*nm(\d{5}|\d{7})$")]
public string ActorId { get; set; }
}
ActorsController.cs
[HttpGet("{actorIdParameter}")]
public async Task<IActionResult> GetActorByIdAsync([FromRoute]ActorIdParameter actorIdParameter)
{
_ = actorIdParameter ?? throw new ArgumentNullException(nameof(actorIdParameter));
// validation result
if (!ModelState.IsValid) //<---this is always false
return ValidationProcessor.GetAndLogInvalidActorIdParameter(method, logger);
}
Code is called using this example: http://localhost:4120/api/actors/nm0000206
There are several other posts which deal with the [FromQuery] and [FromBody] but I can't find anything that deals with the route path. It seems like the {actorIdParameter} needs something to say "get the ActorId property within that object" or something.
I feel like I need the complex object for the regex matching. Alternatively I could switch from the ActorIdParameter object to a string and possibly decorate it inline on the GetActorByIdAsync method but I'm curious if anyone has any suggestions?

Code below works for me using
https://localhost:5001/api/actors/nm0000206
and validation fails correctly for this one
https://localhost:5001/api/actors/42
You don't need any custom handling for this.
public class ActorIdParameter
{
[Required]
[RegularExpression(#"^.*nm(\d{5}|\d{7})$")]
[FromRoute]
public string ActorId { get; set; }
}
[Route("api/actors")]
public class ActorsController : ControllerBase
{
[HttpGet("{actorId}")]
public async Task<IActionResult> GetActorByIdAsync(ActorIdParameter model)
{
if (!ModelState.IsValid)
{
return new BadRequestResult();
}
return new OkResult();
}
}

Try to do GET request to those three, change actors to your controller route :
http://url/actors/nm11111
http://url/actors?actorIdParameter=nm11111
http://url/actors/?actorIdParameter=nm11111
Is any worked ?
Check you model errors ( to understand why it is false ) :
var errors = ModelState
.Where(x => x.Value.Errors.Count > 0)
.Select(x => new { x.Key, x.Value.Errors })
.ToArray();
ModelState.IsValid == false, why?

How do I put things in my RequestBody for my POST Method to find?

I am very new to ASP.NET Core, C#, and RESTful APIs. I'm trying to create a simple practice application right now to practice the different REST commands. The "database" I am working with is a List of objects that have a Name, Age, and Weight.
Currently I am trying to implement a POST method. I could potentially use a [FromQuery] in order to get the data I need for creating the new object and adding it. However, I think it would be better to access it FromBody, especially if I want to add more fields later on.
I don't quite understand/know how I would be able to put stuff/ask the user (??) for data for this in the body. I think I grasp that, when the URL is called, it parses through whatever is in the body of the page/the returned .json and finds it that way, but I don't know how to populate this in the first place.
So far this is just my code for the POST:
[HttpPost]
public ActionResult<List<Objects>> Post([FromQuery] String NewName, [FromQuery] int NewAge, [FromQuery] double NewWeight)
{
return MyList.AddItem(NewName, NewAge, NewWeight);
}
I would love any descriptions on how this works or how I can make this happen...thanks!

Create a model that holds all the required data
public class NewModel {
public String NewName { get; set; }
public int NewAge { get; set; }
public double NewWeight { get; set; }
}
update the action to expect that data and annotate it with [FromBody]
[HttpPost]
public ActionResult<MyModelType> Post([FromBody] NewModel data) {
if (ModelState.IsValid) {
var model = MyList.AddItem(data.NewName, data.NewAge, data.NewWeight);
return model;
}
return BadRequest(ModelState);
}
Consumers of your service would then post a request with the required data in the body of the request and the model binder should populate the model in the controller action.

Comma-seperated model binding

After reading https://www.strathweb.com/2017/07/customizing-query-string-parameter-binding-in-asp-net-core-mvc/
Binding on string array with comma-seperated attribute is a must for us. However, this article only describes how to do this on the method, with simple types. I would prefer to put a attribute on the property on some complex model.
Is this possible?
I can't get it to work otherwise then on the method.
---after edit---
I would like to get this
public class GetCatalogVehiclesRequest
{
[commaseparated]
public string[] Sorting { get; set; }
.....
}
instead of (on controller):
public async Task<IActionResult> Get([commaseperated]GetCatalogVehiclesRequest request, CancellationToken cancellationToken){...}
So on my model instead of an attribute on the parameter.
Any advice?
Thanks!

How do I use WebAPI/Rest correctly when other params are needed

I am new to WebAPI and rest and am trying to do things correctly. By default if I were to access something such as User I would call api/user/5 if I wanted user 5. This would go to my User controller to Get(int num) I think. But I know I will often need other params passed as well. Currently I have Get(JObject data), but that data param is for other parameters. I will need other optional params whether I am sending an ID or wanting a list of everything. How do I go about organizing methods properly with WebAPI? Am I misunderstanding something?
To clarify:
This question is more about REST than dynamic objects, though they play a part:
How do I get a single resource vs a list of resources when I need additional params. I see those concepts as two separate methods, but the additional params complicate it in my mind when routing is involved.

Use attribute routing
For example -
[Route("customers/{customerId}/orders")]
public IEnumerable<Order> GetOrdersByCustomer(int customerId) { ... }
or
[Route("customers/{customerId}/orders/{orderId}")]
public Order GetOrderByCustomer(int customerId, int orderId) { ... }
if you need to return a list, create a method that returns a list, otherwise return the specific item requested

Look into using JToken or the even more dynamic 'dynamic' (Taken from here)
"
JSON and JavaScript is really dynamic, though, and often it's a hassle to try to "deserialize" really dynamic JSON objects into strongly-typed .NET structures. JSON.NET and ASP.NET Web API's model binding offer a happy medium - a middle ground - called JToken.
public class ContactController : ApiController
{
public JToken Post(JToken contact)
{
return contact;
}
}
Using JToken gives a dynamic container but also a DOM-like navigation model. But if that's not dynamic enough for me, why can't my method's parameter just take a "dynamic."
C# is statically typed, sure, but that doesn't mean I can't statically type something dynamic. ;)
Again, note the watch window.
Using dynamic to catch JSON post payloads
public class ContactController : ApiController
{
public dynamic Post(dynamic contact)
{
return contact;
}
}
"

I think you should make a new object for each WebAPI function that will handle the request. You can make the parameters optional with nullable properties.
[HttpPost]
public void SampleFunction(SampleFunctionModel model)
{
}
where SampleFunctionModel is:
public class SampleFunctionModel
{
public int? Id { get; set; }
public string Name { get; set; }
}

POST object in .NET WebAPI

I have a small problem with the WebApi.
Problem:
If I want to post a model using JSON, I can add as many members I want, as long as the members defined in model are present.
Question:
How can I trigger an exception, if an undefined member is present in my Json object. Is this achievable without a custom JsonConverter?
What I'm looking for is a generic solution, not a convertion for every different model.
Example:
Model:
public class Person
{
[Required]
public string Name { get; set; }
}
Api Controller:
public class PersonController : ApiController
{
public HttpResponseMessage Post(Person person)
{
if (person != null)
{
if (ModelState.IsValid)
{
//do some stuff
return new HttpResponseMessage(HttpStatusCode.OK);
}
}
return new HttpResponseMessage(HttpStatusCode.BadRequest);
}
}
Json posts (body)
{"Name":"Joe"} --> valid
{"Name":"Joe","InvalidMember","test","Name","John"} --> also valid. In this case I want to trigger an Exception. Because if you look at it, it doesn't match my modeldefinition exactly.

One thing you could try is playing around with this setting:
config.Formatters.JsonFormatter.SerializerSettings.MissingMemberHandling = MissingMemberHandling.Error;
It should give you an invalid model state when there are extra properties that aren't recognized in the JSON.