Autofac.Core.DependencyResolutionException

Question

I'm new to Autofac and I want to have a better understanding with the following exception. Any help/pointers on this would be highly appreciated!

Getting following Autofac.Core.DependencyResolutionException.

Unhandled Exception: 
    Autofac.Core.DependencyResolutionException: 
        None of the constructors found with 'Public binding flags' on type 'Test.Authorization.LoginService' can be invoked with the available services and parameters: 
         Cannot resolve parameter 'System.Func`1[System.IO.Stream] readStream' of constructor 'Void .ctor(System.Func`1[System.IO.Stream], System.Func`1[System.IO.Stream])'.
    at Autofac.Core.Activators.Reflection.ReflectionActivator.ActivateInstance(IComponentContext context, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Activators\Reflection\ReflectionActivator.cs:line 117    
    at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 79
    at Autofac.Core.Resolving.InstanceLookup.Execute() in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 62
    at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\ResolveOperation.cs:line 124
    at Autofac.Core.Resolving.InstanceLookup.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 115  
    at Autofac.Features.Collections.CollectionRegistrationSource.c__DisplayClass4.c__DisplayClass6.b__1(IComponentRegistration cr) in \autofac\src\Source\Autofac\Features\Collections\CollectionRegistrationSource.cs:line 80    at System.Linq.Enumerable.WhereSelectArrayIterator`2.MoveNext()  
    at System.Linq.Buffer`1..ctor(IEnumerable`1 source)    
    at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
    at Autofac.Features.Collections.CollectionRegistrationSource.c__DisplayClass4.b__0(IComponentContext c, IEnumerable`1 p) in \autofac\src\Source\Autofac\Features\Collections\CollectionRegistrationSource.cs:line 80    
    at Autofac.Core.Activators.Delegate.DelegateActivator.ActivateInstance(IComponentContext context, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Activators\Delegate\DelegateActivator.cs:line 65
    at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 79   
    at Autofac.Core.Resolving.InstanceLookup.Execute() in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 62   
    at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\ResolveOperation.cs:line 124    
    at Autofac.Core.Resolving.InstanceLookup.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 115  
    at Autofac.Core.Activators.Reflection.AutowiringParameter.c__DisplayClass2.b__0() in \autofac\src\Source\Autofac\Core\Activators\Reflection\AutowiringParameter.cs:line 51    
    at Autofac.Core.Activators.Reflection.ConstructorParameterBinding.Instantiate() in \autofac\src\Source\Autofac\Core\Activators\Reflection\ConstructorParameterBinding.cs:line 113    
    at Autofac.Core.Activators.Reflection.ReflectionActivator.ActivateInstance(IComponentContext context, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Activators\Reflection\ReflectionActivator.cs:line 119    
    at Autofac.Core.Resolving.InstanceLookup.Activate(IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 79   
    at Autofac.Core.Resolving.InstanceLookup.b__0() in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 64   
    at Autofac.Core.Lifetime.LifetimeScope.GetOrCreateAndShare(Guid id, Func`1 creator) in \autofac\src\Source\Autofac\Core\Lifetime\LifetimeScope.cs:line 269    
    at Autofac.Core.Resolving.InstanceLookup.Execute() in \autofac\src\Source\Autofac\Core\Resolving\InstanceLookup.cs:line 64   
    at Autofac.Core.Resolving.ResolveOperation.GetOrCreateInstance(ISharingLifetimeScope currentOperationScope, IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\ResolveOperation.cs:line 124    
    at Autofac.Core.Resolving.ResolveOperation.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\ResolveOperation.cs:line 69 
    at Autofac.Core.Resolving.ResolveOperation.Execute(IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Resolving\ResolveOperation.cs:line 96 
    at Autofac.Core.Lifetime.LifetimeScope.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Lifetime\LifetimeScope.cs:line 235    
    at Autofac.Core.Container.ResolveComponent(IComponentRegistration registration, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\Core\Container.cs:line 191    
    at Autofac.ResolutionExtensions.TryResolveService(IComponentContext context, Service service, IEnumerable`1 parameters, Object& instance) in \autofac\src\Source\Autofac\ResolutionExtensions.cs:line 728    
    at Autofac.ResolutionExtensions.ResolveService(IComponentContext context, Service service, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\ResolutionExtensions.cs:line 346    
    at Autofac.ResolutionExtensions.Resolve(IComponentContext context, Type serviceType, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\ResolutionExtensions.cs:line 244    at Autofac.ResolutionExtensions.Resolve[TService](IComponentContext context, IEnumerable`1 parameters) in \autofac\src\Source\Autofac\ResolutionExtensions.cs:line 197    
    at Autofac.ResolutionExtensions.Resolve[TService](IComponentContext context, Parameter[] parameters) in \autofac\src\Source\Autofac\ResolutionExtensions.cs:line 213

Here's my cs code:

    public sealed class AuthorizationModule : Module
    {
        protected override void Load(ContainerBuilder builder)
        {
            builder
            .Register(LoginService)
            .AsImplementedInterfaces()
            .SingleInstance();
        }

     static LoginService LoginService(IComponentContext c)
     {
         var file = c.Resolve<IFile>();
         var dataPath = <Some Path>;

         return new LoginService
         (readStream: () => file.Open(dataPath),
          writeStream: () => file.Create(dataPath));
     }
    }


    sealed class LoginService : TLoginService.Iface, IService
    {
        readonly Func<Stream> _readStream;
        readonly Func<Stream> _writeStream;
        readonly XmlSerializer _serializer;

        public LoginService(
          Func<Stream> readStream,
          Func<Stream> writeStream
        )
        {
           Contract.Requires(readStream != null);
           Contract.Requires(writeStream != null);
           _readStream = readStream;
           _writeStream = writeStream;
           _serializer = new XmlSerializer(typeof (List<LoginRecord>));
     }
     ...
     ...

Answer 1

Your LoginService class has a constructor similar to LoginService(Func<System.IO.Stream> stream). Autofac is unable to create the Func<System.IO.Stream> argument. So register it appropriately so that Autofac can create the LoginService.

Eg:

builder.Register(c => new LoginService(d => File.Open("Foo));

Go through Component Registration section of the Wiki to find which method suits you.