By: Marcel Good

Marcel Good — Mon, 06 Aug 2012 17:31:45 +0000

@Bob Buchanan, the container doesn’t differentiate if you register multiple types with the same contract. It’s up to your code to differentiate when the container gives you all intstances matching a certain contract.

The trick is in what contract you chose to register your type. In MEF for example a contract can be an interface or a class. In addition you can specify a contract name.

For example:

public interface IDependency
{
}

[Export(“A”, typeof(IDependency))]
public class DependencyA : IDependency
{}

[Export(“B”, typeof(IDependency))]
public class DependencyB : IDependency
{
}

[Export]
public class SomeClassWithDependencyToA
{
[ImportingContstructor]
public SomeClassWithDependencyA([Import(“A”)] IDependency dependency)
{
}
}

By: Bob Buchanan

Bob Buchanan — Mon, 06 Aug 2012 16:06:59 +0000

Good article! So with IOC since you take away the “has a”
object created in the class, how does the container differentiate one instance from another of the same type?

Comments on: Dependency Injection

By: Marcel Good

By: Bob Buchanan