While trying to deserialize a complex derived object Json, which is actually created by serializing a viewmodel object in .NET 5 MVC. I am getting the base class properties of the derived object becomes nullified. Also most of the list items in the Viewmodel like SelectList, Ienumnerable<> also become nullified. I tried with a simple inheritance scenario also with 2 properties, unfortunately then also it failed.

Can someone explain how to solve this.

Example

public class Address
{
    public string Street { get; set; }
    public string City { get; set; }
    public string State { get; set; }
    public string PostalCode = "99999"; // initialize properties to generate sample data

    public Address()
    { 
        
    }
}

// This will be serialized into a JSON Contact object
public class Contact : Address
{
    public int Id { get; set; }
    public string Name { get; set; }
    public DateTime? BirthDate { get; set; }
    public string Phone { get; set; }
    public Address Address { get; set; }

    public Contact()
    { 
        
    }
}
public class ContactMain
{
    public Contact contact { get; set; }

    public ContactMain()
    {
        // initialize array of objects in default constructor to generate sample data
        this.contact = new Contact { 
          Id = 7113,
          Name = "James Norris", 
          BirthDate = new DateTime(1977, 5, 13), 
          Phone = "488-555-1212", 
          Address = new Address 
          {
            Street = "4627 Sunset Ave", 
            City = "San Diego",
            State = "CA", 
            PostalCode = "92115" 
          } 
        };

var jsonString = JsonConvert.SerializeObject(contact);

}

Then trying to deserialze it with

JsonConvert.DeserializeObject<Contact>(jsonString);

Makes all the properties in Address Base class null