VB.NET implementing an interface question

  • Thread starter Thread starter Colin McGuire
  • Start date Start date
C

Colin McGuire

Hi all, when I write the class below

Private Class employee

End Class


and then add the line "Implements IVF" which is an interface I have
written, the IDE modifies my code to display

Private Class employee
Implements IVF
Public Function getPerson() As personDetails Implements
IVCO.getPerson
End Function
End Class


The interface defines a single function returning type personDetails.

My question is why is the function declaration in my private class

Public Function getPerson() As personDetails Implements
IVCO.getPerson

and just not

Public Function getPerson() As personDetails

because I already have the "Implements IVF" in the class header. In
other classes I have written, that also implement an interface, I
don't have this "Implements IVCO.getPerson" bit and I'm not sure why,
and if I remove it the compiler complains.

I am running VS2003, .Net runtime 1.1, on a WinXP home computer.

Thank you
Colin


BTW: my interface looks like this and is a separate class/file in my
project.


Public Interface IVF
Function getPerson() As personDetails
End Interface
 
IVCO must be the name of the Module/Class where the definition of the
function is. The IDE will put the stubs in automatically for you. Then you
must implement the interface.

Regards - OHM

Colin said:
Hi all, when I write the class below

Private Class employee

End Class


and then add the line "Implements IVF" which is an interface I have
written, the IDE modifies my code to display

Private Class employee
Implements IVF
Public Function getPerson() As personDetails Implements
IVCO.getPerson
End Function
End Class


The interface defines a single function returning type personDetails.

My question is why is the function declaration in my private class

Public Function getPerson() As personDetails Implements
IVCO.getPerson

and just not

Public Function getPerson() As personDetails

because I already have the "Implements IVF" in the class header. In
other classes I have written, that also implement an interface, I
don't have this "Implements IVCO.getPerson" bit and I'm not sure why,
and if I remove it the compiler complains.

I am running VS2003, .Net runtime 1.1, on a WinXP home computer.

Thank you
Colin


BTW: my interface looks like this and is a separate class/file in my
project.


Public Interface IVF
Function getPerson() As personDetails
End Interface
Click to expand...

Regards - OHM# (e-mail address removed)
 
Sorry that should read.

IVCO must be the name of the Module/Class where the delaration of the
function is.

Regards - OHM#

IVCO must be the name of the Module/Class where the definition of the
function is. The IDE will put the stubs in automatically for you.
Then you must implement the interface.

Regards - OHM



Regards - OHM# (e-mail address removed)
Click to expand...

Regards - OHM# (e-mail address removed)
 
* (e-mail address removed) (Colin McGuire) scripsit:
Private Class employee

End Class


and then add the line "Implements IVF" which is an interface I have
written, the IDE modifies my code to display

Private Class employee
Implements IVF
Public Function getPerson() As personDetails Implements
IVCO.getPerson
End Function
End Class


The interface defines a single function returning type personDetails.

My question is why is the function declaration in my private class

Public Function getPerson() As personDetails Implements
IVCO.getPerson

and just not

Public Function getPerson() As personDetails

because I already have the "Implements IVF" in the class header. In
other classes I have written, that also implement an interface, I
don't have this "Implements IVCO.getPerson" bit and I'm not sure why,
and if I remove it the compiler complains.
Click to expand...

In VB.NET you need to explicitly specify the 'Implements...'. There is
no implicit implementation like in C#. Therefore, in VB.NET, more than
one method can implement a method defined in an interface, and the
method implementing the method of the interface doesn't necessarily have
to have the same name as defined in the interface.
 
Colin,
In addition to the other comments:

Your example seems to be inconsistent!

Given:
Public Class employee

End Class
Click to expand...

Public Interface IVF
Function getPerson() As personDetails
Click to expand...
End Interface

When Employee implements the interface you will get:
Public Class employee
Implements IVF
Public Function getPerson() As personDetails Implements
IVF.getPerson
End Function
End Class
Click to expand...

Your example has "IVCO.getPerson" which would cause a compile error!

As VB.NET requires the Implements statement in the class to signify that the
class implements the interface, plus it needs the Implements clause on each
method that implements a method of the interface. The Implements clause
allows you to rename and/or hide the method from the normal public
"interface" of the class.

For example you can do:
Public Class employee
Implements IVF
Protected Function GetThePersonDetails() As personDetails Implements
IVF.getPerson
End Function
End Class
Click to expand...

Are you perhaps confusing Implements with Inherits? As Inherits does not use
a clause on each method (function, sub, or property).

Hope this helps
Jay
 
Jay, Herfried, OHM# thanks for your comments. I am on the right track
now and still learning more, which you will notice by me not posting
so many questions :)

Jay - thanks. The IVCO was a typo when converting my real code into
something a lot simpler for posting.

Thank you all again
Colin
 
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