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Assignments of references, other than those listed above, require the use of a cast to change the type of the reference.

It is not always possible to perform a successful cast to convert the type of a reference. Whether or not a cast can be successfully performed depends on therelationship of the classes involved in the class hierarchy.

A reference to any object can be assigned to a reference variable of the type Object , because the Object class is a superclass of every other class.

When we cast a reference along the class hierarchy in a direction away from the root class Object toward the leaves, we often refer to it as a downcast .

Whether or not a method can be called on a reference to an object depends on the current type of the reference and the location in the class hierarchy wherethe method is defined. In order to use a reference of a class type to call a method, the method must be defined in or inherited into that class.

Miscellaneous

This section contains a variety of miscellaneous information.

Housekeeping material
  • Module name: Xna0112-Type Conversion, Casting, and Assignment Compatibility
  • File: Xna0112.htm
  • Published: 02/27/14
Disclaimers:

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I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version of the module.

In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale on Amazon.com showing me as the author. Ineither receive compensation for those sales nor do I know who does receive compensation. If you purchase such a book, please beaware that it is a copy of a module that is freely available on cnx.org and that it was made and published withoutmy prior knowledge.

Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.

Complete program listing

A complete listing of the C# program discussed in this module is provided in Listing 11 .

Listing 11 . Project Polymorph02.

/*Project Polymorph02 Copyright 2002, R.G.BaldwinThis program illustrates downcasting Program output is:m in class B *********************************************************/using System; class A {//this class is empty }//end class A//======================================================// class B : A {public void m() { Console.WriteLine("m in class B");}//end method m() }//end class B//======================================================// class C {//this class is empty }//end class C//======================================================// public class Polymorph02 {public static void Main() { Object var = new B();//Following will not compile //var.m();//Following will not compile //((A)var).m();//Following will compile and run ((B)var).m();//Following will compile and run B v1 = (B)var;//Following will not execute. // Causes a runtime exception.//C v2 = (C)var; //Following will not compile//C v3 = (B)var; //Pause until user presses any key.Console.ReadKey(); }//end Main}//end class Polymorph02 //======================================================/

-end-

Questions & Answers

Application of nanotechnology in medicine
what is variations in raman spectra for nanomaterials
Jyoti Reply
I only see partial conversation and what's the question here!
Crow Reply
what about nanotechnology for water purification
RAW Reply
please someone correct me if I'm wrong but I think one can use nanoparticles, specially silver nanoparticles for water treatment.
Damian
yes that's correct
Professor
I think
Professor
what is the stm
Brian Reply
is there industrial application of fullrenes. What is the method to prepare fullrene on large scale.?
Rafiq
industrial application...? mmm I think on the medical side as drug carrier, but you should go deeper on your research, I may be wrong
Damian
How we are making nano material?
LITNING Reply
what is a peer
LITNING Reply
What is meant by 'nano scale'?
LITNING Reply
What is STMs full form?
LITNING
scanning tunneling microscope
Sahil
how nano science is used for hydrophobicity
Santosh
Do u think that Graphene and Fullrene fiber can be used to make Air Plane body structure the lightest and strongest. Rafiq
Rafiq
what is differents between GO and RGO?
Mahi
what is simplest way to understand the applications of nano robots used to detect the cancer affected cell of human body.? How this robot is carried to required site of body cell.? what will be the carrier material and how can be detected that correct delivery of drug is done Rafiq
Rafiq
if virus is killing to make ARTIFICIAL DNA OF GRAPHENE FOR KILLED THE VIRUS .THIS IS OUR ASSUMPTION
Anam
analytical skills graphene is prepared to kill any type viruses .
Anam
what is Nano technology ?
Bob Reply
write examples of Nano molecule?
Bob
The nanotechnology is as new science, to scale nanometric
brayan
nanotechnology is the study, desing, synthesis, manipulation and application of materials and functional systems through control of matter at nanoscale
Damian
Is there any normative that regulates the use of silver nanoparticles?
Damian Reply
what king of growth are you checking .?
Renato
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
?
Kyle
yes I'm doing my masters in nanotechnology, we are being studying all these domains as well..
Adin
why?
Adin
what school?
Kyle
biomolecules are e building blocks of every organics and inorganic materials.
Joe
anyone know any internet site where one can find nanotechnology papers?
Damian Reply
research.net
kanaga
sciencedirect big data base
Ernesto
Introduction about quantum dots in nanotechnology
Praveena Reply
hi
Loga
what does nano mean?
Anassong Reply
nano basically means 10^(-9). nanometer is a unit to measure length.
Bharti
how did you get the value of 2000N.What calculations are needed to arrive at it
Smarajit 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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