VB.Net中文教程(2) 继承与封装性(4)
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 p1 As New FullTime_Teacher("David", 25)
p1.Show()
p1.modifyValue("Kent Smith", 45)
p1.Show()
End Sub
End Class
此程序输出：
Name: David Age: 25
Name: Kent Smith Age: 45
Show()是Person类别的Public程序，孙子类别FullTime_Teacher继承之，成为FullTime_Teacher类别的Public程序，所以Form1_Click()程序能写着指令：p1.Show()。name和modifyAge()是Person的Protected成员，Teacher的modify()程序里能直接使用它们。而且FullTime_Teacher的modifyData()程序里能直接使用它们。但是Form1_Click()就无法使用它们。modify()是Teacher的Protected成员，FullTime_Teacher的modifyValue()程序里能直接使用它们，但Form1_Click()就不行使用。所以若将上述Form1_Click()的指令改为如下，就不对了：
Protected Sub Form1_Click( ..... )
Dim p1 As New FullTime_Teacher("David", 25)
p1.Show()
p1.modify("Kent Smith", 45) Error!
p1.modifyAge(24) Error!
p1.Show()
End SubEnd Class
