Autofac register and resolve

Passing Parameters to Register

When you register components you have the ability to provide a set of parameters that can be used during the resolution of services based on that component. (If you’d rather provide the parameters at resolution time, you can do that instead.)

Available Parameter Types

Parameters with Reflection Components

Parameters with Lambda Expression Components

With lambda expression component registrations, rather than passing the parameter value at registration time you enable the ability to pass the value at service resolution time. (Read more about resolving with parameters.)

In the component registration expression, you can make use of the incoming parameters by changing the delegate signature you use for registration. Instead of just taking in an IComponentContext parameter, take in an IComponentContext and an IEnumerable<Parameter>:

// Use TWO parameters to the registration delegate:
// c = The current IComponentContext to dynamically resolve dependencies
// p = An IEnumerable<Parameter> with the incoming parameter set
builder.Register((c, p) =>
                 new ConfigReader(p.Named<string>("configSectionName")))
       .As<IConfigReader>();

When resolving with parameters, your lambda will use the parameters passed in:

var reader = scope.Resolve<IConfigReader>(new NamedParameter("configSectionName", "sectionName"));

Resolving Services

After you have your components registered with appropriate services exposed, you can resolve services from the built container and child lifetime scopes. You do this using the Resolve() method:

Passing Parameters to Resolve