mthamil / Autofac.Extras.Ordering

An Autofac extension that enables ordered resolution of multiple dependencies.

Autofac.Extras.Ordering

An Autofac extension that adds recognition of IOrderedEnumerable<T> as a relationship type, allowing multiple dependencies to be resolved in a guaranteed order. By default, order is not guaranteed when resolving IEnumerable<T>.

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Usage

First, declare a constructor argument of type IOrderedEnumerable<TDependency> for the component dependent on multiple services:

    public class SomeComponent
    {
        public SomeComponent(IOrderedEnumerable<Dependency> dependencies)
        {
            Dependencies = dependencies;
        }

        public IEnumerable<Dependency> Dependencies { get; private set; }
    }
    
    public class Dependency
    {
        public Dependency(string name)
        {
            Name = name;
        }
        
        public string Name { get; private set; }
    }

Then, register that component as usual:

    builder.RegisterType<SomeComponent>();

Next, register dependencies with the order in which they should be provided using the extension method .OrderBy().

A constant order may be used:

    builder.Register(_ => new Dependency("1"))
           .OrderBy(1);

    builder.Register(_ => new Dependency("2"))
           .OrderBy(2);

Or, a function may be provided that determines the order based on a dependency's own properties:

    builder.Register(_ => new Dependency("1"))
           .OrderBy(d => d.Name);

    builder.Register(_ => new Dependency("2"))
           .OrderBy(d => d.Name);

Finally, add the OrderedRegistrationSource to enable support for IOrderedEnumerable<T>:

    builder.RegisterSource(new OrderedRegistrationSource());

When SomeComponent is resolved, it will be supplied with Dependencies sorted by the order each was given.