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Multiple length 2 constructors. Unity cannot be fixed unambiguously

I want to use DI with a repository class and an interface for MongoDB, but it doesn't work. I have this error:

The MongoRepository`1 type has multiple length 2 constructors. Cannot disambiguate.

Class constructors:

    public MongoRepository(string connectionString, string collectionName)
    {
        this.collection = Util<TKey>.GetCollectionFromConnectionString<T>(connectionString, collectionName);
    }


    public MongoRepository(MongoUrl url, string collectionName)
    {
        this.collection = Util<TKey>.GetCollectionFromUrl<T>(url, collectionName);
    }

Unity Config:

container.RegisterType(typeof(MongoRepository.IRepository<>), typeof(MongoRepository.MongoRepository<>));

How do I set up DI in Unity? Thank!!

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2 answers


The solution is simple: don't use automatic posting when working with frame types as described in this article .

Instead, register a factory delegate for the frame types. This, however, will not work in your case, since you are dealing with a generic type, but working around is simple again: create a derived type and register that:



public class MyMongoRepository<T> : MongoRepository<T>
{
    // of course you should fill in the real connection string here.
    public MyMongoRepository() : base("connectionString", "name") { }
}

container.RegisterType(typeof(IRepository<>), typeof(MyMongoRepository<>));
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Note that you can also tell Unity which constructor it should use:



//Use the MongoRepository(string, string) constructor:
container.RegisterType(
    typeof(IRepository<>), 
    typeof(MyMongoRepository<>),
    new InjectionConstructor(typeof(string), typeof(string)));
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