Using List<interface> within another Interface C#

Question

I'm trying to create an interface for a model class in ASP.NET MVC2 and I wonder if I can use a List<interface> within another interface. It's better if I give a code example.

I have two interfaces, a terminal can have multiple bays. So I code my interfaces like the following.

Bay Interface:

public interface IBay
{
    // Properties
    int id {get; set;}
    string name {get;set;}
    // ... other properties
}

Terminal Interface:

public interface ITerminal
{
    // Properties
    int id {get;set;}
    string name {get;set;}
    // ... other properties
    List<IBay> bays {get;set;}
}

My question is when I implement my class based on these interfaces how to I set up the list of bays. Am I going to have to do the list of bays outside the ITerminal interface and inside the concrete implementation?

My goal is to be able to do the following:

Concrete implementation:
Bay Class:

class Bay : IBay
{
    // Constructor
    public Bay()
    {
        // ... constructor
    }
}

Terminal Class:

class Terminal : ITerminal
{
    // Constructor
    public Terminal()
    {
        // ... constructor
    }
}

And then be able to access the list of bays like this

Terminal.Bays

Any help/suggestions would be greatly appreciated.

Answer 1

You can initialize a list-of-interface by populating it with concrete instances. For example, to initialize your Terminal class using object and collection initializers, you could use code similar to:

Terminal terminal = new Terminal
{
    id = 0,
    name = "My terminal",
    bays = new List<IBay>
    {
        new Bay { id = 1, name = "First bay" },
        new Bay { id = 2, name = "Second bay" },
        new Bay { id = 3, name = "Third bay" },
    }
};

Some points about your code:

• By convention, all public properties should be PascalCased. Use Id or ID instead of id; Name instead of name; Bays instead of bays.
• Since you’re putting so much emphasis on interfaces, you should consider changing the type of the bays property from List<IBay> to IList<IBay>. This would allow consumers to assign IBay[] arrays to it.