Call Base functions from Child in VB.net - vb.net-2010

Question

How to call the base functions in vb.net?
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
It says syntax error when I use MyBase to call the base functions
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

You can't call MyBase from there as the object hasn't yet been constructed.
A better implementation would be:
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
Example
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