Superconstructors?

Superconstructors?

• shido

  Public Class SuperClass

  Public Sub New()

  'Does Something

  End Sub

  End Class

  Public Class SubClass

  Inherits SuperClass

  Public Sub New()

  'Do More

  End Sub

  End Class

   

  What is your end result objective   A contructor is not overridable and if you inherit from the super class you subclass when instatiated will "dosomething" from the base class and will "do More" from its own contructor....You may wish to create overridable methods so the sub class can access the parent class methods...

  
  
  

• suzy_mathew

  Hi,

  You want to use MyBase.New() to call the SuperClass's constructor. It has to be the first statement in the constructor.

  Public Class SubClass
  Inherits SuperClass

  Public d As INteger
  Public e As INteger

  Public Sub New(a As Integer, b As Integer, c As Integer, _
  d As Integer, e As Integer)
  MyBase.New(a,b,c)
  Me.d = d
  Me.e = e
  End Sub
  End Class

  Public Class SuperClass
  Public a As Integer
  Public b As INteger
  Public c As Integer

  Public Sub New(a As INteger, b As Integer, c AS Integer)
  Me.a = a
  Me.b = b
  Me.c = c
  End Sub
  End Class

  
  

• Michael Schroeder

  Thank ya, exactly what I needed.

  And just to make sure, MyBase always goes up one level, right So if I had SuperClass, SubClass and SubSubClass, to access SuperClass's constructor you'd use MyBase.MyBase.New()

  
  

• Bear23

  I think Dick Donny's close... here, let me type what I need to do in Java syntax and hopefully that'll express what I need.

  Public Class SuperClass{

  int a, b, c;

  public SuperClass(int a,int b,int c){

  this.a=a;

  this.b=b;

  this.c=c;

  }

  }

  Public Class SubClass extends SuperClass{

  int d, e;

  public SubClass(int a,int b,int c,int d,int e){

  super(a,b,c);

  this.d=d;

  this.e=e;

  }

  }

  Does that make sense

  
  

• Brandon Waskiewicz

  joynerCN wrote:

  What's the general syntax for using inheritance in VB Say I've got ClassSuper and ClassSub, ClassSub inherits ClassSuper. How do you access the super constructor How do you access values in the super class

  I have assumed that your use of 'super' to refer to a class relates to the ClassSuper type.

  Class ClassSuper : Sub New()

  Class ClassSub : Inherits ClassSuper : Sub New() ... MyBase.New

  In the inheriting class, use of the MyBase keyword exposes methods that the inheriting class has scope to access in the base class (ClassSub). Access to the base class ctor can only be obtained from the ctor of the inheriting class.

  Is that what you were looking for, or did I completely miss the point :)

  Richard

  
  

• potatosnketchup

  joyner,

  You can only access one level up with MyBase.New(). If you want to call up many levels, use Protected Sub New's for the same effect. Protected means they can only be called by children. Here is an example:

  Public Class SubSubClass
  Inherits SubClass

  Public Sub New()
  MyBase.New("Special Functionality")
  End Sub
  End Class

  Public Class SubClass
  Inherits SuperClass

  Public d As Integer
  Public e As Integer

  Protected Sub New(ByVal arg As String)
  MyBase.New(arg) ' Pass args straight up to parent
  End Sub

  Public Sub New(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer, _
  ByVal d As Integer, ByVal e As Integer)
  MyBase.New(a, b, c)
  Me.d = d
  Me.e = e
  End Sub
  End Class

  Public Class SuperClass
  Public a As Integer
  Public b As Integer
  Public c As Integer

  Protected Sub New(ByVal arg As String)
  ' put special functionality for your grandchildren here
  End Sub

  Public Sub New(ByVal a As Integer, ByVal b As Integer, ByVal c As Integer)
  Me.a = a
  Me.b = b
  Me.c = c
  End Sub
  End Class
  

  Hope that helps.
  Matt

  
  
• Superconstructors?