dr = d
 End Sub
 Public Sub Show()
 MessageBox.Show("Engine: " + e.model)
 dr.Show()
 End Sub
End Class
'----------------
Public Class Form1
 Inherits System.WinForms.Form
 Public Sub New()
 MyBase.New()
 Form1 = Me
 'This call is required by the Win Form Designer.
 InitializeComponent()
 'TODO: Add any initialization after the InitializeComponent() call
 End Sub
 'Form overrides dispose to clean up the component list.
 Public Overrides Sub Dispose()
 MyBase.Dispose()
 components.Dispose()
 End Sub
#Region " Windows Form Designer generated code "
 .......
#End Region
 Protected Sub Form1_Click(ByVal sender As Object, ByVal e As System.EventArgs)
 Dim civic As New Car()
 Dim d1 As New Driver("Wang")
 Dim d2 As New Driver("Kao")
 civic.assignTo(d1)
 civic.Show()
 civic.assignTo(d2)
 civic.Show()
 End Sub
End Class

此程序输出﹕
  Model: Honda
  Driver: Wang
  Model: Honda
  Model" Kao

Car之对象诞生后﹐也诞生Engine之对象e ﹔同时立即指定司机﹐如下指令﹕
 
 Dim civic As New Car()
 Dim d1 As New Driver("Wang")
.....
 civic.assignTo(d1)
.....

日常生活中的常见情况﹕汽车对象诞生时﹐不须立即指定司机对象。例如﹐汽车出厂时或闲置时并无司机﹐且汽车经常更换司机。此情形下﹐应先诞生civic对象和d1对象，如下：



此时，未立即指定司机﹔而必要时才以assignTo()程序指定司机。例如，将d1指定给civic对象﹐就令civic内之参考变量dr指向d1 对象，如下：