April 2003
Intermediate to advanced
560 pages
14h 4m
English
Content preview from Programming Visual Basic .NET, Second EditionBecome an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.
NotInheritable Classes
The opposite side of the design coin from MustInherit is
NotInheritable. Just as classes
marked with MustInherit are considered abstract,
classes marked with NotInheritable are considered
sealed
. Although an abstract class is intended
to be derived-from and to provide a template for its subclasses to
follow, a sealed class does not allow classes to derive from it at
all. The NotInheritable keyword placed before the
class declaration precludes derivation. Classes are most often marked
NotInheritable to prevent accidental inheritance.
If the declaration of Window in Example 6-3 is
changed from MustInherit to
NotInheritable, the program will fail to compile.
If you try to build this project, the compiler will return the
following error message:
C:\...Module1.vb(13): 'NotInheritable' classes cannot have members declared 'MustOverride'.
Microsoft recommends using NotInheritable
“when it will not be necessary to create derived
classes”[11] and also
when your class consists of nothing but shared methods and
properties.
[11] Visual Studio .NET Combined Collection: Base Class Usage Guidelines.
Become an O’Reilly member and get unlimited access to this title plus top books and audiobooks from O’Reilly and nearly 200 top publishers, thousands of courses curated by job role, 150+ live events each month,
and much more.
Read now
Unlock full access
More than 5,000 organizations count on O’Reilly
O’Reilly covers everything we've got, with content to help us build a world-class technology community, upgrade the capabilities and competencies of our teams, and improve overall team performance as well as their engagement.Julian F.
I wanted to learn C and C++, but it didn't click for me until I picked up an O'Reilly book. When I went on the O’Reilly platform, I was astonished to find all the books there, plus live events and sandboxes so you could play around with the technology.Addison B.
I’ve been on the O’Reilly platform for more than eight years. I use a couple of learning platforms, but I'm on O'Reilly more than anybody else. When you're there, you start learning. I'm never disappointed.Amir M.
I'm always learning. So when I got on to O'Reilly, I was like a kid in a candy store. There are playlists. There are answers. There's on-demand training. It's worth its weight in gold, in terms of what it allows me to do.