Most of the answers here so far suggest that you change the injected dependency type to some sort of Abstract Factory (a Func<T> is also an Abstract Factory) to address the issue. However, if you do that it would be a leaky abstraction because you would let the knowledge of a particular implementation determine the … Read more
You can configure dependencies with or without names in the API, attributes, or via the config file. You didn’t mention XML above, so I’ll assume you’re using the API. To tell the container to resolve a named dependency, you’ll need to use an InjectionParameter object. For your ClientModel example, do this: container.RegisterType<IClientModel, ClientModel>( new InjectionConstructor( … Read more
Put simply (because it’s not a problem limited to OOP world only), a dependency is a situation where component A needs (depends on) component B to do the stuff it’s supposed to do. The word is also used to describe the depended-on component in this scenario. To put this in OOP/PHP terms, consider the following … Read more
In short, you don’t need a dependency injection container or service locater like you would in C#/Java. Since Node.js, leverages the module pattern, it’s not necessary to perform constructor or property injection. Although you still can. The great thing about JS is that you can modify just about anything to achieve what you want. This … Read more
I am preparing a presentation for a usergroup. As such I just went through a bunch of them. Namely: AutoFac, MEF, Ninject, Spring.Net, StructureMap, Unity, and Windsor. I wanted to show off the 90% case (constructor injection, which is mainly what people use an IOC for anyway). You can check out the solution here (VS2008) … Read more
As a general consideration, circular dependencies indicate a design flaw – I think I can safely say this since you are not the original author of the code 🙂 I wouldn’t consider an Initialize method a good solution. Unless you are dealing with an add-in scenario (which you aren’t), Method Injection is not the right … Read more
The general rule of resources is that: He who owns the resource is responsible of disposing of it. This means that if a class owns a resource, it should either dispose of it in the same method that it created it in (in which case the disposable is called an ephemeral disposable), or if that’s … Read more
You shouldn’t try to supply the AcmeDataContext itself to the EmployeeRepository. I would even turn the whole thing around: Define a factory that allows creating a new unit of work for the Acme domain: Create an abstract AcmeUnitOfWork that abstracts away LINQ to SQL. Create a concrete factory that can allows creating new LINQ to … Read more
UPDATE 2019: With the introduction of Web Forms 4.7.2, there is now better support for DI. This invalidates the below. See: Wiring up Simple Injector in WebForms in .NET 4.7.2 You can use automatic constructor injection by replacing the default PageHandlerFactory with a custom one. This way you can use an overloaded constructor to load … Read more
Consider: class MyClass { //Implementation public void Foo() {} } class SomethingYouWantToTest { public bool MyMethod(MyClass c) { //Code you want to test c.Foo(); } } Because MyMethod accepts only a MyClass, if you want to replace MyClass with a mock object in order to unit test, you can’t. Better is to use an interface: … Read more