Resolving All Objects of a Particular Type

When you want to obtain a list of all the registered objects of a specific type, you can use the ResolveAll method. The two overloads of this method accept either an interface or a type name, and they return an instance of IEnumerable that contains references to all registered objects of that type that are not default mappings. The list returned by the ResolveAll method contains only named instance registrations. The ResolveAll method is useful if you have registered multiple object or interface types using the same type but different names. You can also use the params to provide constructor overrides for the ResolveAll calls.

The ResolveAll Method Overloads

The following table shows the overloads of the ResolveAll method. You can only request a list of objects using the object type. The API for the Unity container contains both generic and non-generic overloads of this method so that you can use it with languages that do not support the generics syntax.

Using the ResolveAll Method

The following examples show how you can retrieve a list of all registered types for a specific registration type. They use the run-time methods of the container to register the types it will resolve. For more information about how you can configure Unity with type registrations and mappings, see Configuring Unity.

// Create container and register types using a name for each one
IUnityContainer myContainer = new UnityContainer();
myContainer.RegisterType<IMyService, DefaultService>();
myContainer.RegisterType<IMyService, DataService>("Data");
myContainer.RegisterType<IMyService, LoggingService>("Logging");

// Retrieve a list of non-default types registered for IMyService
// List will only contain the types DataService and LoggingService
IEnumerable<IMyService> serviceList = myContainer.ResolveAll<IMyService>();

' Create container and register types using a name for each one
Dim myContainer As IUnityContainer = New UnityContainer()
myContainer.RegisterType(Of IMyService, DefaultService)()
myContainer.RegisterType(Of IMyService, DataService)("Data")
myContainer.RegisterType(Of IMyService, LoggingService)("Logging")

' Retrieve a list of non-default types registered for IMyService
' List will only contain the types DataService and LoggingService
Dim serviceList As IEnumerable(Of IMyService) = myContainer.ResolveAll(Of IMyService)

Alternatively, you can use the non-generic methods of the container to achieve the same result, except that the return value this time is an IEnumerable list of type Object.

// Create container and register types using a name for each one
IUnityContainer myContainer = new UnityContainer();
myContainer.RegisterType(typeof(MyServiceBase), typeof(DefaultService));
myContainer.RegisterType(typeof(MyServiceBase), typeof(DataService), "Data");
myContainer.RegisterType(typeof(MyServiceBase), typeof(LoggingService), "Logging");

// Retrieve a list of non-default types registered for MyServiceBase
// List will only contain the types DataService and LoggingService
foreach(Object mapping in myContainer.ResolveAll(typeof(MyServiceBase)))
{
  MyServiceBase myService = (MyServiceBase)mapping;
}

' Create container and register types using a name for each one
Dim myContainer As IUnityContainer = New UnityContainer()
myContainer.RegisterType(GetType(MyServiceBase), GetType(DefaultService))
myContainer.RegisterType(GetType(MyServiceBase), GetType(DataService), "Data")
myContainer.RegisterType(GetType(MyServiceBase), GetType(LoggingService), "Logging")

' Retrieve a list of non-default types registered for MyServiceBase
' List will only contain the types DataService and LoggingService
For Each mapping As Object In myContainer.ResolveAll(GetType(MyServiceBase))
  Dim myService As MyServiceBase = CType(mapping, MyServiceBase)
Next

Resolving All Generic Types by Name

You can use the ResolveAll method with generic types, just as you do with non-generic types, to retrieve an enumerable list of resolved instances for all of the named mappings for a generic type. However, all of the registrations or mappings must resolve to a type that has the same set of type arguments, and you must specify these type arguments in the call to the ResolveAll method.

For more information see Resolving All Objects of a Particular Type.

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