Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
483 views
in Technique[技术] by (71.8m points)

c# - How to bind Generic-type interfaces in Ninject

I'm fairly new to Ninject, and found myself stumbling when I came to implement a generic repository pattern. I want to bind a dependency IRepository<IEntityType> to a class ConcreteRepository<EntityType> where ConcreteRepository<T> implements IRepository<T> and EntityType implements IEntityType. I tried this:

kernel.Bind<IRepository<IEntityType>>().To<ConcreteRepository<EntityType>>();

...but Ninject won't take that because it doesn't know or care that EntityType implements IEntityType. How can I go about binding this dependency?

UPDATE

This is the error I'm getting:

Error 3 The type 'ICM.Dependency.Repository.ConcreteRepository' cannot be used as type parameter 'TImplementation' in the generic type or method 'Ninject.Syntax.IBindingToSyntax.To()'. There is no implicit reference conversion from 'ConcreteRepository<EntityType>' to 'IRepository<IEntityType>'.

SOLUTION

I still don't quite understand why my binding doesn't work, but evidently I was using generics incorrectly there. As such the solution doesn't really relate to NInject. I ended specifying the ConcreteRepository to explicitly connect IEntityType with TEntityType:

public class ConcreteRepository<TInterface, TEntity> : IRepository<TInterface> where TEntity : TInterface { ... }

Then the injection can be written as follows:

kernel.Bind<IRepository<IEntityType>>().To<ConcreteRepository<IEntityType,EntityType>>()
See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Reply

0 votes
by (71.8m points)
kernel.Bind(typeof(IRepository<>)).To(typeof(SimpleRepository<>));

Take a look at my one if you want here: http://blog.staticvoid.co.nz/2011/10/staticvoid-repository-pattern-nuget.html i have binding examples

EDIT:

The error you are getting is saying that your concrete repository isnt an instance of the generic one you want to bind to, ie you will need to do this

public class ConcreteRepository<ConcreteEntity> : IRepository<IEntity>{}

not

public class ConcreteRepository<ConcreteEntity> : IRepository<ConcreteEntity>{}

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
OGeek|极客中国-欢迎来到极客的世界,一个免费开放的程序员编程交流平台!开放,进步,分享!让技术改变生活,让极客改变未来! Welcome to OGeek Q&A Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...