这真的应该返回一个空的 String() 吗？

Question

我有一个属性类：

<AttributeUsage(AttributeTargets.Property)> _
Public Class DirectoryAttribute
    Inherits Attribute

    Private _attribute As String

    Public Sub New(ByVal attribute As String)
        _attribute = attribute
    End Sub

    Public ReadOnly Property Attribute As String
        Get
            Return _attribute
        End Get
    End Property
End Class

以及接口和类：

Public Interface IDirentoryEntity
    <DirectoryAttribute("Name")> _
    Property Name As String
End Interface

Public Interface IOrganizationalUnit
    Inherits IDirectoryEntity
End Interface

Public Class OrganizationalUnit
    Implements IOrganizationalUnit

    ' Implementing IOrganizationalUnit here...'
End Class

Public Interface IIdentifiableDirectoryEntity
    Inherits IDirectoryEntity

    <DirectoryAttribute("sAMAccountName")> _
    Property Login As String
End Interface

Public Interface IGroup
    Inherits IIdentifiableDirectoryEntity
End Interface

Public Class Group
    Implements IGroup

    Private _attributes() As String

    ' Implementing IGroup here...'

    Private ReadOnly Property Attributes() As String()
        Get
            If (_attributes Is Nothing) Then
                Dim attr() As DirectoryAttribute = _
                    CType(GetType(Group).GetCustomAttributes(GetType(DirectoryAttribute), True), DirectoryAttribute())

                If (attr Is Nothing OrElse attr.Length = 0 OrElse attr(0) Is Nothing) Then _
                    Return New String(0) { }

                _attributes = New String(attr.Length) { }

                For index As Integer = 0 To attr.Length - 1 Or _attributes.Length - 1 Step 1
                    _attributes(index) = attr(index).Attribute
                Next
            End If

           Return _attributes
        End Get
    End Property
End Class

话虽如此，Private Property Attributes() As String() 是否应该返回放置在接口上的 DirectoryAttribute 的值属性也是如此，因为我在 Type.GetCustomAttributes 方法的继承参数中指定了 True ？

Answer 1

我认为有两个主要的混淆点：

1. 您的代码正在查找类型的属性，并且这些属性应用于属性。如果您想检索属性，则需要在“登录名”或“名称”等属性上查找它们。
2. 无论如何，继承和实现之间是有区别的。 Group 类实现接口 IGroup，因此当您请求 Group 上的继承属性时，您不会看到在 IGroup 上定义的任何属性。如果您想要类型实现的接口上的属性，则需要直接询问接口，而不能通过类型。