CODEWITHSUNDEEP
nhibernatefluent-nhibernatecomponentsautomappingvalue-objects
Joran
Joran

Reputation: 61

How to automap a collection of components with Fluent NHibernate?

All of my entities and value objects implement marker interfaces IEntity and IValueObject. I have set them up to be treated as components like so:

public override bool IsComponent(Type type)
{
    return typeof(IValueObject).IsAssignableFrom(type);
}

public override bool ShouldMap(Type type)
{
    return typeof(IEntity).IsAssignableFrom(type) || typeof(IValueObject).IsAssignableFrom(type);
}

Unfortunately, this does not seem to allow entities that have collections of value objects to be automapped as component collections. For example:

public class MyEntity : IEntity
{
    public IList<MyValueObject> Objects { get; set; }
}

public class MyValueObject : IValueObject
{
    public string Name { get; set; }
    public string Value { get; set; }
}

Is there any way to define a convention such that, any time an IEntity has an IList of a type that implements IValueObject, it gets mapped as if I had specified:

HasMany(x => x.Objects)
    .Component(x => { 
        x.Map(m => m.Name); 
        x.Map(m => m.Value); 
    });

What I don't want to do is have to manually do these overrides for every class and write out each property for the value object again and again.

Upvotes: 6

Views: 882

Answers (1)

Kronos
Kronos

Reputation: 3111

  1. Create a new class that inherits from HasManyStep (FluentNHibernate.Automapping.Steps).

  2. Override the ShouldMap() method with something like :

    return base.ShouldMap(member) && IsCollectionOfComponents(member)

  3. Add your logic to :

    public void Map(ClassMappingBase classMap, Member member)
{ ... }

  4. Replace the default step with your new one :

    public class MyMappingConfiguration : DefaultAutomappingConfiguration
{
    public override IEnumerable<IAutomappingStep> GetMappingSteps(AutoMapper mapper, IConventionFinder conventionFinder)
    {
        var steps = base.GetMappingSteps(mapper, conventionFinder);
        var finalSteps = steps.Where(c => c.GetType() != typeof(FluentNHibernate.Automapping.Steps.HasManyToManyStep)).ToList();
        var idx = finalSteps.IndexOf(steps.Where(c => c.GetType() == typeof(PropertyStep)).First());
        finalSteps.Insert(idx + 1, new MyCustomHasManyStep(this));
        return finalSteps; 
    }
}

Note : You could also get the original source code of HasManyStep.cs and copy it to your project to introduce your custom logic.

Upvotes: 1

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