How to define a default constructor by code using StructureMap?
I can't figure out how to define the default constructor (when it exists overloads) for a type in StructureMap (version 2.5) by code.
I want to get an instance of a service and the container has to inject a Linq2Sql data context instance into it.
I wrote this in my 'bootstrapper' method :
When I run my app, I got this error :
StructureMap Exception Code: 202 No Default Instance defined for PluginFamily MyNamespace.Data.SqlRepository.MyDataContext, MyNamespace.Data, Version=188.8.131.52, Culture=neutral, PublicKeyToken=null
If I comment out all Linq2Sql generated contructors that I don't need, it works fine.
Update : Oh, and I forgot to say that I would not use the [StructureMap.DefaultConstructor] attribute.
You can specify a constructor with the ConstructedBy(). Please try this:
ForRequestedType<MyDataContext>().TheDefault. Is.ConstructedBy(() => new MyDataContext());
This worked for me.
I'm assuming you'd also need to set the object lifetime (InstanceScope) if you are using Linq2Sql. I'd suggest using this code because it give you a little more flexibility.
ForRequestedType< MyDataContext >() .CacheBy( InstanceScope.PerRequest ) .TheDefault.Is.OfConcreteType< MyDataContext >() SelectConstructor< MyDataContext >( () => new MyDataContext());
With this code you can also further inject interfaces definitions into the MyDataContext constructor like this
SelectConstructor< MyDataContext >( () => new MyDataContext((IDatabaseFactory)null ));
Just remember to define the concrete type with StructureMap for your IDatabaseFactory instance.
I'm not sure how / if it can be done with the fluent interface / internal DSL. You can however use an attribute, if you're not fussed about polluting your domain?
Tag your preferred constructor with [DefaultConstructor] StructureMap defaults to the greediest constructor by convention (constructor with the most parameters).