Enforce interface implementation on propperty

Hi All,

I'm in a situation I need to Expose an object.
the object I need to expose in a namespace I'm not allowed to reference directly as the application is modular and the module can be loaded or not.

In a class I've got this Propperty and function:

Code:

---

Public Property ObjectToExpose As Object Implements IExposedObject.ObjectToExpose
            Get
                Return _ObjectToExpose
            End Get
            Set(value As Object)
                If value IsNot Nothing Then
                    If HasInterfaces(value) Then
                        _ObjectToExpose = value
                        _id = value.id
                    Else
                        Throw New Exception("Item doesn't support Idirty or IselectionListData")
                    End If
                End If
            End Set
        End Property

        Private Function HasInterfaces(ByVal Item As Object) As Boolean

            Dim SelctionInterface As String = "ISelectionListData"
            Dim DirtyInterface As String = "IDirty"
            Dim result As Boolean

            If Item.GetType.GetInterface(DirtyInterface) IsNot Nothing Then
                result = (Item.GetType.GetInterface(SelctionInterface) IsNot Nothing)
            End If

            Return result

        End Function

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How can I enforce that the object has these interfaces in this line?
Public Property ObjectToExpose As Object
Something like:
Public Property (T as {"Idrty","ISelectionListData"}) ObjectToExpose As Object

If the interface defines that property then anything that implements the interface must implement the property. So if your object implements IExposedObject it must, in turn implement the ObjectToExpose property (assuming that's a property on the interface). You don't need to do anything. I have a feeling I might be miss-understanding the question though.

Hi FunkyDexter,

No, IExposedObject is the interface that's implemented. But you did set me on the right way for an escape route

Code:

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Public Property ObjectToExpose As IObjecttoExpose Implements IExposedObject.ObjectToExpose

Interface IObjectToExpose
Inherits Idirty, IselectionListdata
end interface

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The disadvantage is that I need to rewrite every class I want to expose to implement IObjecttoExpose instead of Idirty and ISelectionlistData.