如何在项目vb.net中声明两个具有相同名称的类

Question

I'm starting in vb.net and I'm migrating my project vb6 to vb.net. In my project I have in a file, a class named A, declared as follows:

Public Class A
.....
End Class

In another file I have to declare another class for local use, with the same class name already declared earlier in another file (Class A). But both classes are different.

Then I tried the following:

Public Class Z
  Private _a As A
    Public Property a () As A
        Get
            Return _a
        Get End
        Set (ByVal value As A)
            _a = value
        End Set
    End Property
End Class Z

Class A
......
End Class

Then I tried the following:

Public Class Z
  Private _a As A
    Public Property a () As A
        Get
            Return _a
        Get End
        Set (ByVal value As A)
            _a = value
        End Set
    End Property

Class A
......
End Class

End Class Z

The need is that when instantiating ZI get access local Class A But I have the error message with saying:

Error 4 class 'A' and class 'A', declared in 'C: \\ TFS \\ SigaCom \\ BsControl System 2014 \\ BsSystem \\ nfe \\ A.vb' conflict in namespace 'BSSystemControl'. C: \\ TFS \\ SigaCom \\ BsControl System 2014 \\ BsSystem \\ nfe \\ impostoDevol.VB 12 7 BSControl

If I place the Class A statement within the class Z Scope, I got the following message:

Error 4 'A' is already declared the 'Public Property A The A' in this class. C: \\ TFS \\ SigaCom \\ BsControl System 2014 \\ BsSystem \\ nfe \\ impostoDevol.VB 12 11 BSControl

Answer 1

If your goal is serialization, your class names do not matter in this regard. By default when serializing to XML the properties are what matter, the use of the property name can be overridden using the XmlElement(string) attribute. For instance, given the following structure:

Public Class Z
    Private _a As A2
    <XmlElement("A")> _
    Public Property a () As A2
        Get
            Return _a
        Get End
        Set (ByVal value As A2)
            _a = value
        End Set
    End Property

   Class A2
      '......
   End Class

End Class Z

Will serialize the to the same XML as:

Public Class Z
    Private _a As A2
    <XmlElement("A")> _
    Public Property ZZZZ () As A2
        Get
            Return _a
        Get End
        Set (ByVal value As A2)
            _a = value
        End Set
    End Property

   Class A2
      '......
   End Class

End Class Z

Which will also serialize to the same XML as:

Public Class Z
    Private _a As ZZZZ
    <XmlElement("A")> _
    Public Property CDEF () As ZZZZ
        Get
            Return _a
        Get End
        Set (ByVal value As ZZZZ)
            _a = value
        End Set
    End Property

   Class ZZZZ
      '......
   End Class

End Class Z

Answer 2

The naming of your members does not follow naming conventions. Private objects should be named in camelCase, avoid using the "_" char at start, end, neither in the middle, public properties ans classes in TitleCase, also, names should be intuitive, a kind of short-name of a larger name.

Secondlly, I don't think you need a backing field at all for the sceneraio that you've exposed.

Anyways, to solve the problem that you are having just move each class with same classname to different namespaces with different names, this way you will avoid ambiguity, but that style of programming is incorrect.

If I understood good, this is what you intent to do?:

Public class TopLevelClass

Namespace name1

    Public Class Zclass

        Public Property A As Aclass

        Public Sub New()
            Me.A = New Aclass
        End Sub

        Public NotInheritable Class Aclass
            Public Sub New()
            End Sub
        End Class

    End Class

End Namespace

Namespace name2

    Public Class Zclass

        Public Property A As Aclass

        Public Sub New()
            Me.A = New Aclass
        End Sub

        Public NotInheritable Class Aclass
            Public Sub New()
            End Sub
        End Class

    End Class

End Namespace

End Class