Question

I have 2 fields like

private IFruit fruit;
private Banana banana;

An instance of Banana is created like this:

var banana = new Banana(fruit);

I want to create an attribute for Banana fields to do the job of creating Banana instance for me!

Answer 1

Attributes don’t cause any code to be executed – you’ll have to use reflection to access them. If you want you could implement a base class that has this behavior, and add the reflection code to the constructor:

abstract class AutoCreateBase
{
    public MyBase()
    {
        // Reflection to go through the fields, find the attributes, and use Activator.CreateInstance() on each
    }
}

class MyClass : AutoCreateBase
{
    [AutoCreate]
    private Banana banana;
}