Ninject: call a method with each Get call

Question

I have a Singleton Binding on Ninject and I would like to call a method whenever DI resolves it (i.e. with each Get call). Ninject has OnActivation method that is called when the object is resolved only.

I am aware that using Transient scope will be the intuitive solution but due to out-of-control reason. The object must be singleton.

Answer 1

You can achieve this with some trickery. Let me give you an example:

const string Name = "Foo";

// Singleton Binding. Will only be used when the context uses the {Name}
Bind<Foo>().To<Foo>()
    .Named(Name)
    .InSingletonScope();

// Unnamed binding with method call on each resolution
Bind<Foo>().ToMethod(ctx => 
    {
        // Do anything arbitrary here. like calling a method...
        return ctx.Kernel.Get<Foo>(Name));
    });

When Foo (unnamed) is requested from the kernel it will resolve to the ToMethod binding - where you can insert any arbitrary code you like. In the end, the method must use the kernel to request Foo, but this time with a name-condition. This will resolve to the named singleton binding.