Fluent interfaces and inheritance in C#

Question

I\'ll show a problem by example. There is a base class with fluent interface:

class FluentPerson
{
    private string _FirstName = String.Empty;
    private          


        

Answer 1

 public class FluentPerson
 {
    private string _FirstName = String.Empty;
    private string _LastName = String.Empty;

    public FluentPerson WithFirstName(string firstName)
    {
        _FirstName = firstName;
        return this;
    }

    public FluentPerson WithLastName(string lastName)
    {
        _LastName = lastName;
        return this;
    }

    public override string ToString()
    {
        return String.Format("First name: {0} last name: {1}", _FirstName, _LastName);
    }
}


   public class FluentCustomer 
   {
       private string _AccountNumber = String.Empty;
       private string _id = String.Empty;
       FluentPerson objPers=new FluentPerson();



       public FluentCustomer WithAccountNumber(string accountNumber)
       {
           _AccountNumber = accountNumber;
           return this;
       }

       public FluentCustomer WithId(string id)
       {
           _id = id;
           return this;
       }

       public FluentCustomer WithFirstName(string firstName)
       {
           objPers.WithFirstName(firstName);
           return this;
       }

       public FluentCustomer WithLastName(string lastName)
       {
           objPers.WithLastName(lastName);
           return this;
       }


       public override string ToString()
       {
           return objPers.ToString() + String.Format(" account number: {0}",  _AccountNumber);
       }
   }

And invoke it using

  var ss = new FluentCustomer().WithAccountNumber("111").WithFirstName("ram").WithLastName("v").WithId("444").ToString();