Resolving a class of and object that conforms to protocol

Question

I would like to pass an object that conforms to some protocol, and resolve its type for allocation with Swinject framwork (By dependency injection).

protocol IViewModelAware {
    typealias T
    var viewModel : T { get set }
}


class ViewAndViewModelCreator {
    var container : Container

    init(container : Container) {
        self.container = container
    }

    func resolveViewModel<T : IViewModelAware>(controller : T) {
        let mirror = Mirror(reflecting: controller.viewModel)
        let viewModelClassType = mirror.subjectType
        let viewModel = self.container.resolve(viewModelClassType.self) // This line shows error
        controller.viewModel = viewModel
    }

}

Error: Cannot invoke 'resolve' with an argument list of type '(Any.Type)'

How do I get the Class from an object that confirms to protocol, maybe there is another option except reflection?

Answer 1

You can get the type of the view model class from its instance by controller.viewModel.dynamicType:

func resolveViewModel<T : IViewModelAware>(controller : T) {
    let viewModel = container.resolve(controller.viewModel.dynamicType)
    // ...
}