C# Ninject - Binding Factory Method and Generic

Question

I have a factory method called MessageHandlerFactory

public class MessageHandlerFactory : IMessageHandlerFactory<IMessage>
{
    public IMessageHandler<IMessage> GetMessageHandler()
    {
        return new MessageHandler_1();
    }
}

... and the following message Handler

public class MessageHandler_1 : IMessageHandler<Message>
{
    //Do Something…
}

public class Message : IMessage
{
    public String Name {get; set;}
}

MessageHandlerFactory needs to be assigned to all occurrences of IMessageHandlerFactory in my project so that calls to IMessageHandlerFactory.GetMessageHandler() will return an instance of MessageHandler_1. (In my actual code, I have multiple implementations of IMessageHandler and IMessageHandlerFactory.GetMessageHandler would return an appropriate implementation based on some conditions...). Here is how I do my Ninject binding

Bind<IMessageHandlerFactory<IMessage>>().To<MessageHandlerFactory>();
Bind<IMessageHandler<Message>>().To<MessageHandler_1>();

But when I try accessing the MessageHandlerFactory.GetMessageHandler, I get the following exception

Ninject.ActivationException: Error activating IMessageHandler{IMessage} No matching bindings are available, and the type is not self-bindable. Activation path: 1) Request for IMessageHandler{IMessage}

Wondering how I could fix it? I have been playing with this for quite sometime without any success. Any help would be greatly appreciated!!

your actual implementation must be different from what you provided here, since the code you provided here does not, *ever*, resolve `IMessageHandler`. There is no `IResolutionRoot.Get<..>`. So please provide your *actual* code so we may help. You might also want to look into ninject.extensions.factory - it eliminates the need for implementing factories which do nothing more than `return IResolutionRoot.Get<...>()` — BatteryBackupUnit, May 04 '14 at 08:44

score 0 · Answer 1 · answered Jun 17 '14 at 17:00

Your exception message implies that you are attempting to resolve an "IMessageHandler< IMessage >", and there is no matching binding. The closest you have is a binding for "IMessageHandler< Message >" (note the missing "I"). I'm guessing that's where you're running into a problem.

C# Ninject - Binding Factory Method and Generic

1 Answers1