400元﹐而非原来的100元了。此orange再接受讯息── add(80)﹐其 balance值增加为480 元。orange接到第 2个讯息── add(80)时﹐计算机再执行add() 程序﹐其再度传回orange的参考值﹐使得整个指令──
又成为orange之别名。因之﹐亦能把disp()讯息接于其后﹐如下﹕
''''ex04.bas
Imports System.ComponentModel
Imports System.Drawing
Imports System.WinForms
''''------------------------------------------------------------------------------------
Public Class Money
Private balance As Decimal
Public Sub New(ByVal amount As Decimal)
balance = amount
End Sub
Public Function add(ByVal saving As Decimal) As Money
balance = balance + saving
add = Me
End Function
Public Sub Display()
MessageBox.Show("Balance is " + str(balance))
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 orange As New Money(100)
orange.add(300).add(80).Display()
End Sub
End Class
此程序输出如下﹕Balance is 480
orange对象接到第 1个讯息──add(300)﹐计算机就执行add()程序，执行到结尾指令﹐传回Me（即orange对象）参考值。此时Form1_Click()的orange.add(300)就是orange对象之参考值﹐亦即orange.add() 是orange对象之别名﹔则orange和 orange.add(300)重合在一起﹐代表着同一对象──原来的orange对象。
接下来﹐第 2个讯息──add(80)传给orange.add(300) ﹐相当于传给orange对象。再度执行到 add()里的的add = Me指令时﹐又令orange.add(300).add(80) 成为 orange.add(300)之别名﹐即orange之别名﹔于是﹐三者代表同一对象──原来的orange对象。
接下来﹐第3个讯息──Display传给orange.add(300).add(80) ﹐相当于传给orange对象。
于是输出orange对象内的balance值。
以程序传回Me参考值之技巧将应用于许多方面。为了更了解这种方法﹐请看个特殊情形── 程序传回新对象之参考值。此对象不是目前对象，但内容是从目前对象拷贝而来。这不同于传回Me参考值的情形﹐两种用法常令人搞混﹗现在﹐把程序改为──
''''ex05.bas
Imports System.ComponentModel
Imports System.Drawing
Imports System.WinForms
''''------------------------------------------------------------------------------------
Public Class Money
Private balance As Decimal
Public Sub New(ByVal amount As Decimal)
balance = amount
End Sub
Public Function add(ByVal saving As Decimal) As Money
Dim newobj As Money
newobj = New Money( balance + saving )
add = newobj
End Function
Public Sub Display()
MessageBox.Show("Balance is " + str(balance))
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 orange As New Money(100)
orange.add(300).add(80).Display()
End Sub
End Class
此程序输出如下﹕Balance is 480
当orange对象接到第 1个讯息──add(300)﹐计算机就执行add()程序﹐诞生一个Money类别的新对象﹐把目前对象内容（即orange对象之值）拷贝一份给Form1_Click()。这份拷贝就是orange.add(300)之值。
orange.add(300) 即为拷贝回来的那份对象﹐并非原来的orange对象。当讯息──add(80)传给orange.add(300)所代表的对象时﹐计算机就执行add()函数﹐此时目前对象是orange.add(300) 而非原来的orange。执行时﹐又把目前对象──orange.add(300)内容拷贝一份给新诞生的对象，传回给Form1_Click()程序﹐这份拷贝就是orange.add(300).add(80) 之值。
由于每回执行add()就产生一份新对象（虽然内容相同﹐但占不同的内存空间）﹐其后的讯息皆传给add()所诞生之新对象﹐而非orange对象，所以这些讯息皆不影响原来orange对象之内容。
请注意﹕Display()并未传回对象之参考值﹐则Display()讯息之后不得再接其它讯息了。所以﹐如果Form1_Click()程序改写如下，那就错了──
Protected Sub Form1_Click( ByVal sender As Object,
ByVal e As System.EventArgs)
Dim orange As New Money(100)
orange.add(300).Display().add(80) ''''Error!
End Sub
End Class
因Display()不传回对象之参考值﹐则指令──
其后之讯息──add(80) 是错的。如何改正呢﹖很简单﹐只需叫Display()程序传回 Me（目前对象之参考值）或新对象之参考值即可﹐如下﹕
''''ex06.bas
Imports System.ComponentModel
Imports System.Drawing
Imports System.WinForms
''''-------------------------------------------------------------------------------------
Public Class Money
Private balance As Decimal
Public Sub New(ByVal amount As Decimal)
balance = amount
End Sub
Public Function add(ByVal saving As Decimal) As Money
Dim newobj As Money
newobj = New Money( balance + saving )
add = newobj
End Function
Public Function Display() As Money
MessageBox.Show("Balance is " + str(balance))
Display = Me
End Function
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 orange As New Money(100)
orange.Display().add(300).Display().add(80).Display()
End Sub
End Class
此程序输出﹕
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