对象设计模式的已定义组合

Question

My head is hurting trying to figure out which would be the best design pattern after researching some on the internet. The problem I am trying to solve, is the creation of combination of objects.

For example, I have object combinations where an Event object will need to be created with a defined number of Task objects:

Event 1 - Task 1, Task 2, Task 3

Event 2 - Task 2, Task 3

Ideally, I want a simple way of creating Event objects, without something like:

Event.Add(Task1)
Event.Add(Task2)

etc etc Ideally I want to see something like Event1.Add(Task1).Add(Task2).Add(Task3).

I also need to be able to retrieve the Tasks from Events as separate objects on their own.

And the Tasks need to be re-usable.

Answer 1

How about a Builder Pattern

public class Event {
    public Event(IEnumerable<Task> tasks) {...}
}

with a builder api like so

new EventBuilder().AddTask(....).AddTask(....).AddTask(....).Build();

Answer 2

You can do a little fluent foo like so...

var e = new EventFoo().Add(new Task()).Add(new Task()) ;

public class EventFoo
{
    public EventFoo()
    {
        Tasks = new List<Task>();
    }
    public List<Task> Tasks { get; private set; }

    public EventFoo Add(Task task)
    {
        Tasks.Add(task);
        return this;
    }
}

If you have a regular set of events to create, you can also move their creation to a factory.