實現與子類的接口

Question

我有以下接口：

Interface IViewModel 
    ... 
End Interface 

Interface ISpecialViewModel 
    Inherits IViewModel 
    ... 
End Interface 

Interface IView 
    WriteOnly Property MyViewModel As IViewModel 
End Interface 

以下是我的課：

Class VerySpecialViewModel 
    implements ISpecialViewModel 
    ... 
End Class 

Class View 
    Implements IView 

    Public WriteOnly Property MyViewModel As VerySpecialViewModel Implements IView.MyViewModel 
     ... 
    End Property 
End Class 

它告訴我，「MyViewModel」無法實現「MyViewModel」因爲沒有在'IView'接口上匹配屬性。

Answer 1

Public Interface ISomething 
    WriteOnly Property Prop As IParent 
End Interface 

該接口聲明不滿足您的類實現。請考慮以下情況：

有一個叫IChild2另一個接口：

Public Interface IChild2 
    Inherits IParent 
    ... 
End Interface 

根據ISomething接口，你應該能夠實現IChild2類的實例分配到Thing.Prop，因爲它繼承了IParent。但你不能，因爲Thing.Prop屬性是IChild類型和IChild2不會繼承IChild

更新

什麼有關解決方案：

Class ThingBase 
    Implements ISomething 

    Public WriteOnly Property Prop As IParent Implements ISomething.Prop 
     Set(value As IParent) 

     End Set 
    End Property 
End Class 

Class Thing 
    Inherits ThingBase 

    Public Overloads WriteOnly Property Prop As IChild 
     Set(value As IChild) 
      MyBase.Prop = value 
     End Set 
    End Property 
End Class 

UPDATE2

Interface IView(Of T As IViewModel) 
    WriteOnly Property MyViewModel As T 
End Interface 

Class VerySpecialViewModel 
    Implements ISpecialViewModel 
End Class 

Class View 
    Implements IView(Of ISpecialViewModel) 

    Public WriteOnly Property MyViewModel As ISpecialViewModel Implements IView(Of ISpecialViewModel).MyViewModel 
     Set(value As ISpecialViewModel) 

     End Set 
    End Property 
End Class 

或

Class View 
    Implements IView(Of VerySpecialViewModel) 

    Public WriteOnly Property MyViewModel As VerySpecialViewModel Implements IView(Of VerySpecialViewModel).MyViewModel 
     Set(value As VerySpecialViewModel) 

     End Set 
    End Property 
End Class