Solved

Need to inherit a class such that variables in the base class are determined in the inherited class

Posted on 2006-06-24
7
169 Views
Last Modified: 2010-04-23
The best way to explain this is with this watered-down example:

public class BaseClass
    public function getEncoded(Arg1 as string, Arg2 as string) as string
          return BCODE + ";" + Arg1 + ";" + Arg2
    end function
end class

public class Class1
     inherits BaseClass
     public const BCODE as string = "AABBCC"
end class


How do I do this?  (the example above gives an error, since BCODE doesn't exist in the base class)
0
Comment
Question by:stev0931
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 4
  • 2
7 Comments
 

Author Comment

by:stev0931
ID: 16976698
I know that in C++, you can declare something as virtual so that it knows it will be able to find it when the time comes.  Maybe there is an equivelant in VB.NET?
0
 

Author Comment

by:stev0931
ID: 16976730
Another thought: maybe there is a way to do this using interfaces?
0
 
LVL 13

Accepted Solution

by:
iHadi earned 250 total points
ID: 16976838

public class BaseClass
    public function getEncoded(BCODE as string, Arg1 as string, Arg2 as string) as string
          return BCODE + ";" + Arg1 + ";" + Arg2
    end function
end class

public class Class1
     inherits BaseClass
     public const BCODE as string = "AABBCC"
end class
0
Creating Instructional Tutorials  

For Any Use & On Any Platform

Contextual Guidance at the moment of need helps your employees/users adopt software o& achieve even the most complex tasks instantly. Boost knowledge retention, software adoption & employee engagement with easy solution.

 

Author Comment

by:stev0931
ID: 16976849
Thanks!
0
 
LVL 30

Expert Comment

by:Alexandre Simões
ID: 16976869

To avoid having to pass it as a parameter on the function, you could declare an overridable property BCODE on the base class.
Inheriting from it, you just had to override it and set you value.
On you example you use a Constant... you can create a ReadOnly property to simulate that.

Example:

    Public Overridable ReadOnly Property BCODE() As String
        Get
            Return String.Empty
        End Get
    End Property

    Public Function getEncoded(ByVal BCODE As String, ByVal Arg1 As String, ByVal Arg2 As String) As String
        Return BCODE + ";" + Arg1 + ";" + Arg2
    End Function

End Class

Public Class inheritedClass
    Inherits baseClass

    Public Overrides ReadOnly Property BCODE() As String
        Get
            Return "AABBCC"
        End Get
    End Property



Alex :p

0
 
LVL 30

Expert Comment

by:Alexandre Simões
ID: 16976872
Sorry... Copy/Paste error...
I left the BCODE parameter on the getEncoded finction...

This is the correct one:


    Public Overridable ReadOnly Property BCODE() As String
        Get
            Return String.Empty
        End Get
    End Property

    Public Function getEncoded(ByVal Arg1 As String, ByVal Arg2 As String) As String
        Return BCODE + ";" + Arg1 + ";" + Arg2
    End Function

End Class

Public Class inheritedClass
    Inherits baseClass

    Public Overrides ReadOnly Property BCODE() As String
        Get
            Return "AABBCC"
        End Get
    End Property
0
 

Author Comment

by:stev0931
ID: 16976890
Thanks Alex!
0

Featured Post

On Demand Webinar - Networking for the Cloud Era

This webinar discusses:
-Common barriers companies experience when moving to the cloud
-How SD-WAN changes the way we look at networks
-Best practices customers should employ moving forward with cloud migration
-What happens behind the scenes of SteelConnect’s one-click button

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Suggested Solutions

Title # Comments Views Activity
how to remove error in database 6 52
VB.NET System.NullReferenceException 1 40
VB.net Excel VSTO Add-in version compatability 2 33
CHANGE FORM TEXT BEFORE IT SHOW TO USER 13 30
Introduction When many people think of the WebBrowser (http://msdn.microsoft.com/en-us/library/2te2y1x6%28v=VS.85%29.aspx) control, they immediately think of a control which allows the viewing and navigation of web pages. While this is true, it's a…
If you need to start windows update installation remotely or as a scheduled task you will find this very helpful.
How to Install VMware Tools in Red Hat Enterprise Linux 6.4 (RHEL 6.4) Step-by-Step Tutorial
Exchange organizations may use the Journaling Agent of the Transport Service to archive messages going through Exchange. However, if the Transport Service is integrated with some email content management application (such as an antispam), the admini…

738 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question