我可以从泛型类继承而不指定类型吗？

Question

我在VB.NET控制台应用程序中有以下示例代码。它编译和工作，但感觉像一个黑客。有没有一种方法来定义EmptyChild，以便它继承自Intermediate（Of T As Class）而不使用虚拟EmptyClass？

Module Module1 
Sub Main() 

    Dim Child1 = New RealChild() 
    Child1.Content = New RealClass() 
    Dim Child2 = New EmptyChild() 

    Console.WriteLine("RealChild says: " & Child1.Test) 
    Console.WriteLine("EmptyChild says: " & Child2.Test) 
    Console.ReadLine() 
End Sub 

Public Class EmptyClass 

End Class 

Public Class RealClass 

    Public Overrides Function ToString() As String 
     Return "This is the RealClass" 
    End Function 

End Class 

Public MustInherit Class Base(Of T As Class) 

    Private _content As T = Nothing 
    Public Property Content() As T 
     Get 
      Return _content 
     End Get 
     Set(ByVal value As T) 
      _content = value 
     End Set 
    End Property 

    Public Overridable Function Test() As String 
     If Me._content IsNot Nothing Then 
      Return Me._content.ToString 
     Else 
      Return "Content not initialized." 
     End If 
    End Function 

End Class 

Public MustInherit Class Intermediate(Of T As Class) 
    Inherits Base(Of T) 

    'some methods/properties here needed by Child classes 

End Class 

Public Class RealChild 
    Inherits Intermediate(Of RealClass) 

    'This class needs all functionality from Intermediate. 

End Class 

Public Class EmptyChild 
    Inherits Intermediate(Of EmptyClass) 

    'This class needs some functionality from Intermediate, 
    ' but not the Content as T property. 

    Public Overrides Function Test() As String 
     Return "We don't care about Content property or Type T here." 
    End Function 

End Class 
End Module 

其他的方式做这将是移动的通用代码出来的基类，然后创建这样第二中级班：

Public MustInherit Class Intermediate 
    Inherits Base 

    'some methods/properties here needed by Child classes 

End Class 

Public MustInherit Class Intermediate(Of T As Class) 
    Inherits Intermediate 

    'implement generic Content property here 

End Class 

然后RealChild将从通用的中级继承和EmptyChild将从非泛型中间体继承。我的解决方案的问题是基类是在一个单独的程序集中，我需要保留处理该程序集中泛型类型的代码。并且Intermediate类中的功能不属于带有Base类的程序集。

Answer 1

是的，您需要在继承时指定类型参数，否则您的EmptyChild也必须是通用的。但是，您不必虚设一个EmptyClass - 只需使用Object作为您的类型参数：

Public Class EmptyClass 
    Inherits Intermediate(Of Object) 
End Class