[英]How do shared members from a base class react when a derived object is instantiated when the base class is not in VB.Net?
[英]How can I supress a property or method from a base-class in a derived class in VB.NET?
假设一个基类
Public Class airplane
Private var_num_seats As Integer
Private var_num_engines As Integer
Protected Property num_seats As Integer
Get
Return var_num_seats
End Get
Set(ByVal param_num_seats As Integer)
var_num_seats = param_num_seats
End Set
End Property
Protected Friend Property num_engines As Integer
Get
Return var_num_engines
End Get
Set(ByVal param_num_engines As Integer)
var_num_engines = param_num_engines
End Set
End Property
Protected Friend Sub take_off()
'Do take off tasks
End Sub
Protected Friend Sub start_engines()
'start each engine
End Sub
End Class
还有一个儿童班
Public Class glider
Inherits airplane
Private var_towed As Boolean
Private var_glide_rate As Double
Public ReadOnly Property towed As Boolean
Get
Return var_towed
End Get
End Property
Public ReadOnly Property glide_rate As Double
Get
Return var_glide_rate
End Get
End Property
Public Sub to_glide()
'do gliding
End Sub
End Class
显然,我不希望类Glider具有方法“ start_engines”和属性“ num_engines”。 否则,其他子类可能会有。 我如何在子类中禁止这些属性和方法,而不仅仅是忽略(如果可以的话)?
谢谢!
你不能!
原因:破坏了面向对象!!!!
假设您有:
public void ThisIsAMethod(Airplane plane)
{
plane.start_engines();
}
现在,您可以这样使用它:
Airplane aPlane = new Glider();
ThisIsAMethod(aPlane);
哦,不,aPlane确实是滑翔机,因此您不应调用它。 然而,它是飞机,因此具有该方法。
解:
Hackmode! 在滑翔机中:
受保护的好友Sub start_engines()抛出新的NotSupportedException()End Sub
我怀疑您正在寻找使用界面。
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