Inheritance with VB.NET 2005 - Dealing with constructors with parameters during inheritance
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The previous section already introduced you to constructors in inheritance. Now, I shall extend the discussion to constructors with parameters. Let us modify our hierarchy of classes as follows:
Public Class First
Private m_x As Integer
Private m_y As Integer
Public Sub New(ByVal a As Integer, ByVal b As Integer)
m_x = a
m_y = b
End Sub
...
End Class
Public Class Second
Inherits First
Private m_z As Integer
Public Sub New(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer)
MyBase.New(a, b)
m_z = c
End Sub
...
End Class
Public Class Third
Inherits Second
Public Sub New()
MyBase.New(0, 0, 0)
End Sub
Public Sub New(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer)
MyBase.New(10, 20, 30)
End Sub
...
End Class
Once you modify the hierarchy as above, let us try to modify the testing code as well:
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
Dim obj As New Third(10, 20, 30)
With obj
Me.Label1.Text = "Sum = " & .getSum & ", Product = " & .getProduct
End With
End Sub
You can observe that I am using a new keyword, "MyBase." It is mainly used to access any of the super class members. In this case, I am executing the constructor of the super class by using "MyBase."
In this article, I simply wanted to explain the topics of inheritance in OOPS. The sample codes given in this article are neither the best in performance nor the best in programming methodologies.
Any feedback, suggestions, bugs, errors, improvements etc., are highly appreciated at jag_chat@yahoo.com.
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