abstract class methods overriding the methods of another abstract class - oop

Question

Lets say that I have this line of code:
public abstract class User
{
public string name;
public string email;
public string password;
public abstract void Create();
public abstract void Remove();
public abstract void Modify();
}
And then another abstract class:
public abstract class AbstractCustomer : User
{
public string address;
public Order order;
public abstract override void Create(string n,string e,string pa,int ph,string a);
public abstract override void Modify(string e, string pa, int ph, string a);
public abstract override void Remove(Order o);
public abstract void PlaceOrder(Item i);
public abstract void MakePayment(Order o);
}
and we have the customer which implements the AbstractCustomer:
public class Customer : AbstractCustomer
{
public override void Create(string name, string email, string password, int phoneNum, string address)
{
this.name = name;
this.email = email;
this.password = password;
this.phoneNum = phoneNum;
this.address = address;
this.isActive = true;
ConnectionToDB.SaveCustToDB();
}
public override void Remove(Order order)
{
order.CancelOrder();
}
public override void Modify(string email, string password, int phoneNum, string address)
{
ConnectionToDB.UpdateCustInDB();
}
public override void PlaceOrder(Item item)
{
order = new Order(item);
}
public override void MakePayment(Order order)
{
ConnectionToDB.SavePayToDB(order);
}
}
and this is where the problem starts (this is a helper class whose purpose is to call the methods easily)
public static void Create(AbstractCustomer user, string name, string email, string password, int phoneNum, string address)
{
user.Create(name, email, password, phoneNum, address);
}
public static void Remove(AbstractCustomer user, Order order)
{
user.Remove(order);
}
public static void Modify(AbstractCustomer user, string email, string password, int phoneNum, string address)
{
user.Modify(email, password, phoneNum, address);
}
public static void PlaceOrder(AbstractCustomer user, Item item)
{
user.PlaceOrder(item);
}
public static void MakePayment(AbstractCustomer user, Order order)
{
user.MakePayment(order);
}
These lines of codes produces errors like:
VS will tell you that the Customer class didn't implement the User's abstract methods(well, I think I did because I tried overriding it in the AbstractCustomer). But apparently, we don't need to override it in the Abstract class because the child class(Customer) will automatically inherits it and from there you can just directly override the methods. I found the explanation here overriding abstract methods in an inherited abstract class
But by doing the above solution, it presents another problem. The AbstractCustomer class will lose its purpose and therefore the HelperClass can't call any methods because its static classes depends on the AbstractCustomer that will be passed in the method.
So for the questions: (Problem: Grouping the methods into a static class for me to call it easily)
Is there a way to fix this kind of problem?(I'm thinking of using decorator pattern)
If I use the decorator pattern, what is the purpose of the ConcreteComponent?Is it okay if I remove it?
If I don't use the decorator pattern, is there any pattern available for this kind of problem?
If I don't use any pattern, is there any way to solve this?
Thanks for reading! Sorry coz its a long one! :)

Answer 1

Your solution is not related to Decorator pattern. Decorator - it is something, that should be inherited from existing abstraction (AbstractCustomer in your case) and add extra logic to it (it can be logging, or it can be extra check of each method's parameters for null, or something like that...). See this link.
Btw, I don't like the way how you construct your abstractions. It is better to have well-grained interfaces for each of your methods, e.g. ICanCreate for Create() method, ICanRemove for Remove() method, etc. It allows you to control further types which will implement that functionality. E.g., one customer can implement only ICanCreate interface, another one - ICanCreate + ICanRemove, etc.