'class1
Public Class Class1
    Public Event Changed(sender As Object, e As System.EventArgs)

    Private _nome As String
    Public Property Nome() As String
        Get
            Return _nome
        End Get
        Set(value As String)
            _nome = value
            RaiseEvent Changed(Me, New EventArgs)
        End Set
    End Property
End Class

'module1
Module Module1
    Public TheClass As New Class1
End Module

'form1
Public Class Form1
    Private WithEvents _theclass As Class1

    Private Sub Form1_Load(sender As Object, e As System.EventArgs) Handles Me.Load
        _theclass = TheClass
    End Sub

    Private Sub Button1_Click(sender As System.Object, e As System.EventArgs) Handles Button1.Click
        _theclass.Nome = "Pippo"
    End Sub

    Private Sub _theclass_Changed(sender As Object, e As System.EventArgs) Handles _theclass.Changed
        MsgBox("Changed")
    End Sub
End Class