C# Observer Pattern instance tutorial

This article briefly describes the C# observer model in an example form and shares it with you for your reference. The specific implementation method is as follows:

Now suppose there is a software company that will notify some customers of the information whenever a new product is launched.

Abstract the notification action into an interface. The code looks like this:

public interface IService
{
    void Notif();
}

If a customer wants to get notification, he needs to implement the above interface. The customers here are seen as observers.

public class CustomerA : IService
{
    public void Notif()
    {
      ("Customer A has received the notification~~");
    }
}
public class CustomerB : IService
{
    public void Notif()
    {
      ("Customer B received the notification~~");
    }
}

As a software company, it maintains a collection of customers and provides methods to register and cancel registration, adding or deleting customers to this collection. Whenever there is a notification, it traverses the client collection and lets the IService execute the notification. A software company can be regarded as an object to be observed, or the source of the action.

public class MyCompany
{
    private IList<IService> subscribers = new List<IService>();
    public void Subscribe(IService subscriber)
    {
      (subscriber);
    }
    public void CancelSubscribe(IService subscriber)
    {
      (subscriber);
    }
    public void SendMsg()
    {
      foreach (IService service in subscribers)
      {
        ();
      }
    }
}

The client creates software company instances, creates observer instances, registers or cancels observers, etc.

class Program
{
    static void Main(string[] args)
    {
      MyCompany company = new MyCompany();
      IService customerA = new CustomerA();
      IService customerB = new CustomerB();
      (customerA);
      (customerB);
      ();
      ();
    }
}

Summarize:

①Abstract the action of a notification into an interface
② If an observer wants to receive notifications, he/she implements the notification interface.
③ The object being observed does 3 things: maintain the set of observers, register/cancel the observer, initiate an action to traverse the set of observers, and let the notification interface do things

I hope this article will be helpful to everyone's C# programming learning.