I have a type (at runtime), I want to use it with an IOC container (in this case StructureMap) to find a generic implementation using this type. How do I do that?

It’s simpler than you’d think:

Type genericType = typeof (AbstractValidator);
Type type = genericType.MakeGenericType(bindingContext.ModelType);

//Structure Map container
var instance = _container.GetInstance(type);