Question

I use this tutorial to create Plugin Architecture in my solution and I also use ninject for the first time:

http://www.codeproject.com/script/Articles/ArticleVersion.aspx?aid=358360&av=526320&msg=4308834#xx4308834xx

Now in MVC application while user is in the process of checkout I get the payment method he selects and need to retrieve the plugin for the selected payment method. I have succeeded in retrieving plugin controller this way, though I have no idea whether it is safe or acceptable practice:

Type type = Type.GetType(paymentMethod.PaymentMethodPluginType);  

 //get plugin controller

var paymentController = ServiceLocator.Current.GetInstance(type) as BasePaymentController;

//get validations from plugin

    var warnings = paymentController.ValidatePaymentForm(form);

        //get payment info from plugin

        var paymentInfo = paymentController.GetPaymentInfo(form);
        //…

I also need to access a plugin class for processing the payment.
I have an interface IPaymentMethod

  public partial interface IPaymentMethod 
  {
   void  PostProcessPayment (PostProcessPaymentRequest postprocessPaymentRequest);        

  }

And plugin PaymentProcessor like this

public class PluginPaymentProcessor :IPaymentMethod
    {        
        public void PostProcessPayment (PostProcessPaymentRequest postprocessPaymentRequest)
        {
            ///
        }

Now in MVC project I try to access PostProcessPayment method this way 

IPaymentMethod pluginpaymentmethod = ServiceLocator.Current.GetInstance<IPaymentMethod>(paymentMethod.PaymentProcessor);

here paymentMethod.PaymentProcessor is “MyApp.Plugins.MyPlugin.PluginPaymentProcessor, MyApp.Plugins.MyPlugin,Version=1.0.0.0,Culture=neutral,PublicKeyToken=null”

   And want to use pluginpaymentmethod like i do in controller example

pluginpaymentmethod.PostProcessPayment(postProcessPaymentRequest);

but it throws error that resource is not found and pluginpaymentmethod is not loaded. How can I fix it or can you suggest any tutorial with similar implementations? Thank you.

Answer 1

assuming you have a concrete class called MyPlugin which has the IPaymentMethod interface, then your ninject bindings should look a bit like:

private static void RegisterServices(IKernel kernel){
    kernel.Bind<IPaymentMethod>().To<MyPlugin>().InRequestScope();
}

check that this is in place in your NinjectWebCommon.cs class under the App_Start folder. A trickier scenario might be that IPaymentMethod has to be registered in the same way that the Ninject IKernel is bound:

kernel.Bind<Func<IKernel>>().ToMethod(ctx => () => new Bootstrapper().Kernel);

that would potentially be a trickier issue to work out.