Question

I am trying to add a dependency to a class property using Unity Configuration and also the types I am trying to inject are generic. I had a ‘Google’ about and found I need to use the ‘1 syntax. I am following a tutorial by David Hayden on the Validation Application block BUT, instead of programmatically registering the type I am setting it up through the config file.

<typeAliases>     <!-- Lifetime manager types -->     <typeAlias alias='singleton' type='Microsoft.Practices.Unity.ContainerControlledLifetimeManager,Microsoft.Practices.Unity' />     <typeAlias alias='external' type='Microsoft.Practices.Unity.ExternallyControlledLifetimeManager,Microsoft.Practices.Unity' />     <typeAlias alias='IValidator`1' type='MySerivice.IValidator`1,MyService' />     <typeAlias alias='VABValidator`1' type='MySerivice.VABValidator`1,MyService' />     <typeAlias alias='MyService' type='MySerivice.MyService,MyService' /> </typeAliases> 

Then I register the mappings and properties here:

<types>       <type type='MyService'>     <typeConfig extensionType='Microsoft.Practices.Unity.Configuration.TypeInjectionElement Microsoft.Practices.Unity.Configuration'>       <property name='Validator' propertyType='IValidator`1'/>     </typeConfig>   </type>   <type type='IValidator`1' mapTo='VABValidator`1'>     <lifetime type='singleton' />   </type> </types> 

Inside the MyService I have the following Property:

private IValidator<RegExpressionObject> validator;  [Dependency] public IValidator<RegExpressionObject> Validator {     get { return validator; }     set { validator = value; } } 

When I run this however I get the following exception which is really making me scratch my head:

System.InvalidOperationException: The property Validator on type MyService is of type IValidator’1, and cannot be injected with a value of type IValidator’1

Any help is greatly appreciated.

Answer 1

I believe you’re looking for this syntax:

<typeAlias alias='VABValidator`1'             type='MySerivice.VABValidator`1                 [[Assembly.Namespace.RegExpressionObject,Assembly]],MyService'/> 

That will specify the type of your generic parameter and allow you to inject it.

This functionality is not very well documented 🙂