Custom IServiceProvider in WPF

Question

Is it possible to add a custom IServiceProvider in WPF for use in markup extensions?
I'm not finding any relevant documentation or examples.

Answer 1

The ProvideValue method lets you override anyways whatever logic you desire to overcome the shortcoming of overriding IServiceProvider. I have not tried out the code below, instead it is a sketch of how we could design a custom service provider, preferably as a singleton and other functionality that is usual to add in a dependency inversion framework. You should use the IServiceProvider that is naturally available in your solution due to framework / libs being used or add a DI framework yourself to register interfaces and concrete types.

The MarkupExtension will need to override ProvideValue. You can ignore the IServiceProvider argument here and instead use something you have control over yourself (that is, another IServiceProvider)

  public override object ProvideValue(IServiceProvider
    serviceProvider)
    {
     //retrieve objects from a custom IServiceProvider instead
     var someService = someCustomServiceProvider.GetSomeInstance<ISomeService();
     //use someService to do desired functionality and finally return the object to return in the ProvideValue method here.

}

Where we have some service provider we implement ourselves :

public class SomeCustomServiceProvider : IServiceProvider {

    private readonly Dictionary<T, Func<T>> _registry;

    public SomeCustomServiceProvider(){
     _registry = new Dictionary<T, Func<T>>();
    }

    public void RegisterService<T>(Func<T> createFunc){
     _registry[T] = createFunc;
    }

     public override object GetService(Type serviceType) {
      return _registry[T]();
     }

}

Instead of writing a small DI framework yourself, either use the DI framework which you already are using, e.g. Autofac or similar, or make use of a simple container registry. There are a lot of such small frameworks, I have just added a sample here as an illustration. One example of a DI framework can be SimpleInjector: SimpleInjector