How map C# class to angular object

I have an object class and i want to use it in my asp.net core angular project. I can’t map the object return throuth the http get method. Any options please?

class file:

[Serializable]
public class PricesRules
{
    public HashSet<Price> Prices { get; set; }
    public HashSet<Customer> Customers { get; set; }
    public HashSet<Payment> Payments { get; set; }
}
component.ts :

public prices: PricesRules;

constructor(private http: HttpClient, @Inject('BASE_URL') private baseUrl: string) {
  http.get<PricesRules>(baseUrl + 'api/UpdatePrices/GetLastPrices').subscribe(result => {
      this.prices = result[0];
}, error => console.error(error));
}

interface PricesRules {
Prices: any[];
Customers: any[];
Payments: any[];

}

controller file:

    [HttpGet("[action]")]
    public IEnumerable<PricesRules> GetLastPrices()
    {
        PricesRules pricesRules = null;
        //some code here
        yield return pricesRules;
    }

In my component i have good values in my result object, but my object prices in undefined after…

Thanks

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