Added Decorate() method to KernalBase

[garrypas]

Hi guys,

Firstly I'm relatively new to Ninject so I don't pretent to understand all of the functionality. Also a big thanks to everyone who has contributed to this project :-)

When I started using it one thing I really wanted was to be able to easily decorate a registered type with another type, so I could pass the decorated type into the constructor of the decorator. I know I can achieve this, but the examples I've seen require the decorator to be declared with the class it is decorating. I wanted to simply apply each class one on top of the next in a pipeline, in quite a loosely coupled way, but specifically without the decorator knowing the concrete class it is decorating.

With the code I've added I can now do this like so:

var _module = new StandardKernel();
_module.Bind<IT>().To<T1>().Named("x1");
_module.Decorate<IT, T2>().Named("x2");
_module.Decorate<IT, T3>().Named("x3");
var obj = _module.Get<IT>();
obj.Call(); //Invokes T3 -> Call();

Given the code below

public class T1 : IT
{
    public void Call()
    {
        Console.WriteLine("T1");
    }
}

public class T2 : IT
{       
    private IT _t;

    public T2(IT t)
    {
        _t = t;
    }
    public void Call()
    {
        _t.Call();
        Console.WriteLine("T2");
    }
}

public class T3 : IT
{
    private IT _t;

    public T3(IT t)
    {
        _t = t;
    }
    public void Call()
    {
        _t.Call();
        Console.WriteLine("T3");
    }
}

public interface IT
{
    void Call();
}

I'm not sure if this would be of any use to the community (if not perhaps it can be adapted slightly?), but I wanted to share just in case.

Thanks