Unity IOC container and how to resolve different instances of the same interface

问题

I have a unity container that I am registering types within like so:

    IUnityContainer container = new UnityContainer()
.RegisterType<ITaxAuthorityRateService, TaxAuthorityPopulationRateService>( "PopulationRate" )
.RegisterType<ITaxAuthorityRateService, TaxAuthorityBusinessLicenseRateService>( "BusinessLicenseRate" );

Then I also want to register 2 different services that take a ITaxAuthorityRateService variable in their constructor. Both services need a different class that derives from ITaxAuthorityRateService. How can I handle that situation?

回答1:

Ok I figured it out. Keeping the names the same during registration is correct ("PopulationRate" and "BusinessLicenseRate"). All I had to do was add an attribute to the ITaxAuthorityRateService parameter within the constructor of each service like so:

Service1 constructor parameter:

[Dependency( "BusinessLicenseRate" )]
ITaxAuthorityRateService rateService

Service2 constructor parameter:

[Dependency( "PopulationRate" )]
ITaxAuthorityRateService rateService

And then each service received the correct ITaxAuthorityRateService instance.

来源：https://stackoverflow.com/questions/2343532/unity-ioc-container-and-how-to-resolve-different-instances-of-the-same-interface