Question

I would like to conditionally supply a constructor argument to StructureMap based on the parent type.
I am trying to achieve this with the code below.

The concrete type ProcessorSettings is a constructor argument to both TypeOne and TypeTwo.
ProcessorSettings’s constructor takes one int parameter named “frequency”.

When I try this I get a StructureMap error StructureMap Exception Code: 202
No Default Instance defined for PluginFamily . There is no more information in the error message.

x.ForConcreteType<ProcessorSettings>()
    .Configure.Ctor<int>("frequency")
    .Is(condition => condition.Conditional(y =>
    {
        y.If(t => t.ParentType == typeof(TypeOne))
            .ThenIt.Is.IsThis(intVal1);

        y.If(t => t.ParentType == typeof(TypeTwo))
            .ThenIt.Is.IsThis(intVal2);
    }));

Answer 1

Try using named instances instead of the conditional. If you have many variations, you can create a Convention to reduce duplication.

x.For<ProcessorSettings>().Add<ProcessorSettings>().Ctor<int>("frequency")
    .Is(intVal1).Named("ProcessorSetting1");
x.For<ProcessorSettings>().Add<ProcessorSettings>().Ctor<int>("frequency")
    .Is(intVal2).Named("ProcessorSetting2");
x.For<IType>().Add<TypeOne>().Ctor<ProcessorSettings>()
    .Named("ProcessorSetting1");
x.For<IType>().Add<TypeTwo>().Ctor<ProcessorSettings>()
    .Named("ProcessorSetting2");