如何将事件从通用列表中的子对象传递给父对象？

here is my example code:

这是我的示例代码:

Public Class Parent
    Private _TestProperty As String
    Private WithEvents _Child As IList(Of Child)

    Public Property Test() As String
        Get
            Return _TestProperty
        End Get
        Set(ByVal value As String)
            _TestProperty = value
        End Set
    End Property

    Public Property Child() As IList(Of Child)
        Get
            Return _Child
        End Get
        Set(ByVal value As IList(Of Child))
            _Child = value
        End Set
    End Property

    Private Sub eventHandler Handles _Child
End Class

Public Class Child
    Private _TestProperty As String
    Public Event PropertyChanged As EventHandler

    Friend Sub Notify()
        RaiseEvent PropertyChanged(Me, New EventArgs())
    End Sub

    Public Property Test() As String
        Get
            Return _TestProperty
        End Get
        Set(ByVal value As String)
            _TestProperty = value
            Notify()
        End Set
    End Property
End Class
Public C