The type '' is not assignable to service '' in Autofac

Question

I am now doing a dynamic query in my project by using System.Linq.Dynamic. I use Autofac as my default IOC container. But Now I get a problem on registering generic components, here is my code :

the interface:

public interface IDynamicQuery
{
    IQueryable<T> CreateDynamicQuery<T>(string propertyName, string propertyValue, Expression<Func<T, bool>> where) where T:class;
}

the class:

public class DynamicQuery :IDynamicQuery
{
    public DynamicQuery(IUnitOfWork unitOfWork)
    {
        this.unitOfWork = unitOfWork;
    }
    private  readonly IUnitOfWork unitOfWork;

    public IQueryable<T> CreateDynamicQuery<T>(string propertyName, string propertyValue, Expression<Func<T, bool>> where) where T:class
    {
        var appRepository = unitOfWork.Repository<T>();

        IQueryable<T> queryResult = null;
        if (propertyName.Contains('$'))  
            propertyName = propertyName.Replace('$', '.');
        queryResult = appRepository.GetMany(where).Where("" + propertyName + ".Contains(\"" + propertyValue + "\")");
        return queryResult;
    }
}

Then I register them in the application start entry:

builder.RegisterType<IDynamicQuery>().As<DynamicQuery>().InstancePerHttpRequest();

But When I start up my project based on MVC 4, it throws me an exception like :

 The type 'TinyFrame.Framework.Query.IDynamicQuery' is not assignable to service 'TinyFrame.Framework.Query.DynamicQuery'.

the Exception throws at : var container = builder.Build();

I know how to register a generic class in autofac, but I don't know how to register above class I raised, anyone can help me on this? I am a new comer to autofac, thx in advice.

You have it the wrong way round. An `IDynamicQuery` is not a `DynamicQuery` but a `DynamicQuery` IS an `IDynamicQuery`. — Aron, Apr 28 '14 at 01:24
@Aron Oh my god, how careless of me..... I had a bad sleep last night. thx for advice. — CharlieShi, Apr 28 '14 at 01:32

score 46 · Accepted Answer · edited Mar 09 '15 at 17:23

46

@CharlieShi I had the same problem and I noticed that I was forgetting to add inheritance to my class. But in your case, try this:

builder.RegisterType<DynamicQuery>().As<IDynamicQuery>().InstancePerHttpRequest();

reverse the interface with the class!

edited Mar 09 '15 at 17:23

superjos

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answered Dec 23 '14 at 13:30

Alisom Martins

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5

D'oh. I'd forgotten to add the interface to my class too. It's is Friday, so that's my excuse. – RichS May 04 '18 at 15:10
@RichS hahaha, it's happen guy! – Alisom Martins May 04 '18 at 19:43
2

THIS part of your comment really helped me!! --> I was forgetting to add inheritance – Missy Dec 09 '19 at 21:04

score 13 · Answer 2 · edited Jun 19 '17 at 12:58

13

In my case, I had reversed the order in which the interface and the classes are to be mentioned:

builder.RegisterType<CONCRETE_CLASS>().As<INTERFACE>();

edited Jun 19 '17 at 12:58

Bugs

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answered Jun 19 '17 at 12:39

Sheena Agrawal

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score 7 · Answer 3 · answered Apr 30 '18 at 14:45

7

This can be done if you forget to add the Interface to your class.

builder.RegisterType<People>().As<IPeople>();

This will cause the error

public class People

This will resolve it

public class People : IPeople

answered Apr 30 '18 at 14:45

MyDaftQuestions

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This was my issue – Dino Jul 06 '20 at 23:35
Thank you! This was my issue. It's funny how you can miss little things like this. – Jonathon Cowley-Thom May 14 '21 at 12:20

score 0 · Answer 4 · answered Apr 01 '16 at 12:15

You can register the complete assembly with autofac container like this way:

 builder.RegisterAssemblyTypes(
            typeof(YourClass).Assembly)
            .AsImplementedInterfaces()
            .InstancePerLifetimeScope();

In your case, if you want to register the perticular type only, then just use the following:

builder.RegisterType<DynamicQuery>()
             .As<IDynamicQuery>()
             .InstancePerLifetimeScope();

You can set the lifetime according to your business requirements.

score 0 · Answer 5 · answered Feb 03 '17 at 09:02

0

Your problem is that you try to map interface on implementation, just swap IDynamicQuery and DynamicQuery. And don't forget to make a rebuild.

It should be like:

builder.RegisterType<DynamicQuery>().As<IDynamicQuery>().InstancePerHttpRequest();

answered Feb 03 '17 at 09:02

Denis Kotenko

83
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score 0 · Answer 6 · edited Mar 02 '18 at 21:24

0

Encountered the same problem but the cause was different in my case. I didn't see that I was registering the same type twice. I find this error message is misleading.

edited Mar 02 '18 at 21:24

Cristik

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answered Mar 02 '18 at 21:17

j.e.

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The type '***' is not assignable to service '***' in Autofac

6 Answers6

The type '' is not assignable to service '' in Autofac