I've registered my generic interface in Autofac, but as I resolve it exception is thrown.
Autofac.Core.Registration.ComponentNotRegisteredException: The requested service 'MyCLI.Command.ICommandHandler`1[[MyCLI.Command.ICommand, MyCLI, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' has not been registered.
To avoid this exception, either register a component to provide the service, check for service registration using IsRegistered(), or use the ResolveOptional() method to resolve an optional dependency.
static void Main(string[] args)
{
ContainerBuilder builder = new ContainerBuilder();
var container = builder.RegisterTypes();
var invoker = new Invoker(container);
var command = TypeHelper.GetCommandByDescriptor("LS");
invoker.Dispatch(command);
Console.Read();
}
public static IContainer RegisterTypes(this ContainerBuilder builder)
{
builder.RegisterAssemblyTypes(Assembly.GetExecutingAssembly())
.AsClosedTypesOf(typeof (ICommandHandler<>)).AsImplementedInterfaces();
return builder.Build();
}
public class Invoker : IInvoker
{
private readonly IContainer container;
public Invoker(IContainer container)
{
this.container = container;
}
public void Dispatch<T>(T command) where T : ICommand
{
//if (!container.IsRegistered(typeof(ICommandHandler<>))) return;
var candidate = container.Resolve<ICommandHandler<T>>();
candidate.Execute(command);
}
}
public static ICommand GetCommandByDescriptor(string descriptor)
{
var classes = GetAllCommands();
var command = classes.First(x => x.GetType()
.GetCustomAttributes<CommandDescriptorAttribute>().First().CommandName.Equals(descriptor, StringComparison.OrdinalIgnoreCase));
return command;
}
I got the solution, thank to @Nkosi.
As I return ICommand
from GetCommandByDescriptor(string descriptor)
the type T
in Dispatch Method would be from ICommand
type which is actually not registered, I should return a type which have implemented ICommand
e.g. ListOfDirectoryCommand
.
As well I go like this:
invoker.Dispatch((dynamic)command);
So the type of command
would be specified in run time.