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The C# programmer has control over the code that is executed in response to the event. However, the C# programmer has no control over the fact that a Button object will respond to such an event. The fact that a Button will respond to certain event types is an inherent part of the type specification for the Button class and can only be modified by modifying the source code for the Button class.


If abstraction is the design or specification of a new type, then encapsulation is its definition and implementation.

A programmer defines the data representation and the behavior of an abstract data type into a class, thereby defining its implementation and its interface.That data representation and behavior is then encapsulated in objects that are instantiated from the class.

Expose the interface and hide the implementation

According to good object-oriented programming practice, an encapsulated design usually exposes the interface and hides the implementation. This isaccomplished in different ways with different languages.

Just as most of us don't usually need to care about how the steering mechanism of a car is implemented, a user of a class should not need to careabout the details of implementation for that class.

The user of the class (the using programmer) should only need to care that it works as advertised. Of course this assumes that the user of the class hasaccess to good documentation describing the interface and the behavior of objects instantiated from the class.

Should be able to change the implementation later

For a properly designed class, the class designer should be able to come back later and change the implementation, perhaps changing the type of data structureused to store data in the object, and the using programs should not be affected by the change.

Class member access control

Object-oriented programming languages usually provide the ability to control access to the members of a class. For example, C#, C++ and Java all use thekeywords public , private , and protected to control access to the individual members of a class. In addition, Java adds a fourth level of access control, which is called package-private . C# adds two levels of access control that are not included in Java or C++ (see the next section).

Five levels of access control

According to the C# specifications , "Each member of a class has an associated accessibility, which controlsthe regions of program text that are able to access the member." There are fivelevels of access control in C#:

  • public - Access not limited
  • protected - Access limited to this class or classes derived from this class
  • internal - Access limited to this program
  • protected internal - Access limited to this program or classes derived from this class
  • private - Access limited to this class

A different interpretation

Another online source provides a different interpretation for two of the access levels:

  • The internal modifier declares that a member is known throughout all files in an assembly, but unknown outside that assembly.
  • The protected internal access level can be given only to class members.
  • A member declared with protected internal access is accessible within its own assembly or to derived types.

Questions & Answers

Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
What fields keep nano created devices from performing or assimulating ? Magnetic fields ? Are do they assimilate ?
Stoney Reply
why we need to study biomolecules, molecular biology in nanotechnology?
Adin Reply
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
what school?
biomolecules are e building blocks of every organics and inorganic materials.
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
sciencedirect big data base
Introduction about quantum dots in nanotechnology
Praveena Reply
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
do you think it's worthwhile in the long term to study the effects and possibilities of nanotechnology on viral treatment?
Damian Reply
absolutely yes
how to know photocatalytic properties of tio2 nanoparticles...what to do now
Akash Reply
it is a goid question and i want to know the answer as well
characteristics of micro business
for teaching engĺish at school how nano technology help us
Do somebody tell me a best nano engineering book for beginners?
s. Reply
there is no specific books for beginners but there is book called principle of nanotechnology
what is fullerene does it is used to make bukky balls
Devang Reply
are you nano engineer ?
fullerene is a bucky ball aka Carbon 60 molecule. It was name by the architect Fuller. He design the geodesic dome. it resembles a soccer ball.
what is the actual application of fullerenes nowadays?
That is a great question Damian. best way to answer that question is to Google it. there are hundreds of applications for buck minister fullerenes, from medical to aerospace. you can also find plenty of research papers that will give you great detail on the potential applications of fullerenes.
what is the Synthesis, properties,and applications of carbon nano chemistry
Abhijith Reply
Mostly, they use nano carbon for electronics and for materials to be strengthened.
is Bucky paper clear?
carbon nanotubes has various application in fuel cells membrane, current research on cancer drug,and in electronics MEMS and NEMS etc
so some one know about replacing silicon atom with phosphorous in semiconductors device?
s. Reply
Yeah, it is a pain to say the least. You basically have to heat the substarte up to around 1000 degrees celcius then pass phosphene gas over top of it, which is explosive and toxic by the way, under very low pressure.
Do you know which machine is used to that process?
how to fabricate graphene ink ?
for screen printed electrodes ?
What is lattice structure?
s. Reply
of graphene you mean?
or in general
in general
Graphene has a hexagonal structure
On having this app for quite a bit time, Haven't realised there's a chat room in it.
what is biological synthesis of nanoparticles
Sanket Reply
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Source:  OpenStax, Xna game studio. OpenStax CNX. Feb 28, 2014 Download for free at https://legacy.cnx.org/content/col11634/1.6
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