Injecting different dependencies with Simple Injector depending on assembly

Question

I have two different IContext implementations living in different assemblies (in fact they are in different solutions). These assemblies are both used in a single parent project. This parent project uses SimpleInjector for DI.

Is there a way of getting Simple Injector to inject/register different implementations based on the assembly location of the class being injected into?.

In pseudo-fudge code, something like:

// if assembly/namespace of class being injected into is MyApp.ProjectFoo;
container.Register(typeof(IContext), typeof(FooContext));

// if assembly/namespace of class being injected into is MyApp.ProjectBar;
container.Register(typeof(IContext), typeof(BarContext));

Answer 1

This can be done using the RegisterConditional method:

container.RegisterConditional<IContext, FooContext>(
    c => c.Consumer.ImplementationType.Assembly.Name.Contains("MyApp.ProjectFoo"));
container.RegisterConditional<IContext, BarContext>(
    c => c.Consumer.ImplementationType.Assembly.Name.Contains("MyApp.ProjectBar"));

If the check for the assembly name is a recurring pattern, you can extract this to a useful method:

private static Predicate<PredicateContext> InAssembly(string assemblyName) =>
    c => c.Consumer.ImplementationType.Assembly.Name.Contains(assemblyName)

You can use this method as follows

container.RegisterConditional<IContext, FooContext>(InAssembly("MyApp.ProjectFoo"));
container.RegisterConditional<IContext, BarContext>(InAssembly("MyApp.ProjectBar"));