來自VB.net的Child的調用函數

Question

如何在vb.net中調用基函數？

Imports System.Data.Sql 
Imports System.Data.SqlClient 

Public Class Box 
    Public length As Double ' Length of a box 
    Public breadth As Double ' Breadth of a box 
    Public height As Double ' Height of a box 
    Public function setLength(ByVal len As Double) 
     length = len 
    End Sub 
    Public Sub setBreadth(ByVal bre As Double) 
     breadth = bre 
    End Sub 
    Public Sub setHeight(ByVal hei As Double) 
     height = hei 
    End Sub 
    Public Function getVolume() As Double 
     Return length * breadth * height 
    End Function 
End Class 

它說語法錯誤，當我使用MyBase調用基函數

Public Class myChild : Inherits Box 
    'box 1 specification 
    MyBase.setLength(6.0) 
    MyBase.setBreadth(7.0) 
    MyBase.setHeight(5.0) 

    'box 2 specification 
    MyBase.setLength(12.0) 
    MyBase.setBreadth(13.0) 
    MyBase.setHeight(10.0) 

    'volume of box 1 
    volume = MyBase.getVolume() 
    Console.WriteLine("Volume of Box1 : {0}", volume) 

    'volume of box 2 
    volume = MyBase.getVolume() 
End Class 

Answer 1

爲對象尚未建立不能從那裏調用MyBase。

較好的實施方法是：

Box.vb

Public Class Box 
    Private mLength As Double ' Length of a box 
    Private mBreadth As Double ' Breadth of a box 
    Private mHeight As Double ' Height of a box 

    Public Sub New(ByVal length As Double, ByVal breadth As Double, ByVal height As Double) 
     Me.mLength = length 
     Me.mBreadth = breadth 
     Me.mHeight = height 

    End Sub 
    Public Property Length As Double 
     Get 
      Return Me.mLength 
     End Get 
     Set(ByVal value As Double) 
      Me.mLength = value 
     End Set 
    End Property 

Public Property Breadth As Double 
    Get 
     Return Me.mBreadth 
    End Get 
    Set(ByVal value As Double) 
     Me.mBreadth = value 
    End Set 
End Property 

Public Property Height As Double 
    Get 
     Return Me.mHeight 
    End Get 
    Set(ByVal value As Double) 
     Me.mHeight = value 
    End Set 
End Property 

Public Function getVolume() As Double 
    Return Length * Breadth * Height 
End Function 
End Class 

Child.vb

Public Class Child : Inherits Box 

    Public Sub New(ByVal length As Double, ByVal breadth As Double, ByVal height As Double) 
     MyBase.New(length, breadth, height) 
    End Sub 

End Class 

例

Sub Main() 
     Dim box1 As New Child(6.0, 7.0, 5.0) 
     Dim box2 As New Child(12.0, 13.0, 10.0) 

     Console.WriteLine("box1 volume is: {0}", box1.getVolume()) 
     Console.WriteLine("box2 volume is: {0}", box2.getVolume()) 
    End Sub