Question

I have 2 classes like this:

1)

public class EFInitializerLanguage : EFInitializerBase, IRepositoryInitializer<Language>
{
    public IEntityRepository<Language> Create()
    {
        return this.Model.CreateObjectContext<LanguageData>(new SqlConnection(Utility.ConnectionStrings.ConnDefault));
    }
}

2)

public class EFInitializerPerson : EFInitializerBase, IRepositoryInitializer<Person>
    {
        public IEntityRepository<Person> Create()
        {
            return this.Model.CreateObjectContext<PersonData>(new SqlConnection(Utility.ConnectionStrings.ConnDefault));
        }
    }

And the definition in Unity.config is (probably these are wrong and I couldn’t figure out what to do)

<unity>
    <typeAliases>
<typeAlias alias="IRepositoryInitializer`1" type="Contracts.Repositories.IRepositoryInitializer`1, Contracts" />
        <typeAlias alias="EFInitializerPerson" type="Data.Initializers.EFInitializerPerson, Data" />

    <typeAlias alias="IRepositoryInitializerLanguage`1" type="Contracts.Repositories.IRepositoryInitializer`1, Contracts" />
    <typeAlias alias="EFInitializerLanguage" type="Data.Initializers.EFInitializerLanguage, Data" />
<containers>
        <container>
            <types>
<type type="IRepositoryInitializer`1" mapTo="EFInitializerPerson" />
        <type type="IRepositoryInitializerLanguage`1" mapTo="EFInitializerLanguage" />
</types>
        </container>
    </containers>
</unity>

You might think to use 1 EFInitializer instead of 2 or more, but because of the input and out type difference I couldnt not make it. At this point, I believe my current approach seems fine to me.

The error I get during RunTime is:

Resolution of the dependency failed, type =
“Contracts.DataManagers.ILanguageManager”, name = “”. Exception
message is: The current build operation (build key Build
Key[Contracts.DataManagers.ILanguageManager, null]) failed: The
current type, Contracts.DataManagers.ILanguageManager, is an
interface and cannot be constructed. Are you missing a type mapping?
(Strategy type BuildPlanStrategy, index 3)

It seems like, in the config file, the declarations must be different when it comes down to have 2 different classes that implements SAME interface.

I’d be very happy if you could point me out to the right direction.

Thanks in advance,

Answer 1

I cannot say this is an exact solution for my problem. But I thought of a workaround; Instead of using 2 EFInitializers, I merged in to one with generic types as in below:

public class EFInitializer<T, TP>: EFInitializerBase, IRepositoryInitializer<T> 
        where T : class
        where TP : ObjectContext, IEntityRepository<T>
    {
        public IEntityRepository<T> Create()
        {
            return this.Model.CreateObjectContext<TP>(new SqlConnection(Utility.ConnectionStrings.ConnDefault));
        }
    }

and the unity configuration became into this:

<unity>
    <typeAliases>
<typeAlias alias="IRepositoryInitializer`1" type="Contracts.Repositories.IRepositoryInitializer`1, Contracts" />
        <typeAlias alias="EFInitializer`2" type="Data.Initializers.EFInitializer`2, Data" />
</typeAliases>
    <containers>
        <container>
            <types>
<type type="IRepositoryInitializer`1" mapTo="EFInitializer`2" />
</types>
        </container>
    </containers>
</unity>

Well, with this approach at least I would not have to write EFInitializer for each entity which is pretty cool for me.

As a result, this solution is not an exact match for my problem. Since, I still am working on the system design, perhaps I’ll run into same problem.

Thank you for your help.