Dependency is not injected

Topics: CAB & Smart Client Software Factory
Aug 17, 2006 at 4:34 AM
originally posted by: AmanAnwari


I'm new to CAB and object builder, understands DI

I was working with Object builder, created two classes ClassA (with default constructor) and ClassB (with constructor accepting ClassA reference, marked with constructor injection attribute), i was expecting ClassB to get previously created ClassA reference present in the locator's weak reference dictionary.

Here is the code

Public Class ClassA

Public id As String

Public Sub New()
id = System.Guid.NewGuid.ToString
End Sub

End Class

Public Class ClassB

Private m_o As DefaultConstructorType

Public Sub New()

End Sub

<InjectionConstructor()> _
Public Sub New(ByVal dep As ObjectBuilderTutorials.DefaultConstructorType)
m_o = dep
End Sub

End Class


-----Test code-------------

Dim bld As New Builder
Dim loc As New ObjectBuilder.Locator

Dim a1 As Object = bld.BuildUp(loc, Type.GetType("ObjectBuilderTutorials.ClassA"), Nothing, Nothing)
Dim b1 As ClassB = bld.BuildUp(Of ClassB)(loc, "y", Nothing)

Current result b1 gets a new instance of ClassA and not a1.
Expected result: b1 getas instance a1

If this results are right then how do i achieve my expected results without creating ClassA as singleton?

Aug 17, 2006 at 8:09 PM
originally posted by: mamu300B


you have to add your newly created item to the locator.

And in C# your code would like this:

Builder bld = new Builder();
IReadWriteLocator loc = new Locator();

object a1 = bld.BuildUp(loc, typeof(ClassA), null, null);

loc.Add(new DependencyResolutionLocatorKey(typeof(ClassA), null), a1);

ClassB b1 = bld.BuildUp<ClassB>(loc, "y", null);

Hope this helps
Aug 18, 2006 at 1:15 PM
originally posted by: AmanAnwari

Yep, thanks it works