This article is designed to further your knowledge about properties in the C# language. Read how Rajesh uses get and set methods to access these properties.
In C#, properties are nothing but natural extension of data fields. They are usually known as ‘smart fields’ in C# community. We know that data encapsulation and hiding are the two fundamental characteristics of any object oriented programming language. In C#, data encapsulation is possible through either classes or structures. By using various access modifiers like private, public, protected, internal etc it is possible to control the accessibility of the class members.
Usually inside a class, we declare a data field as private and will provide a set of public SET and GET methods to access the data fields. This is a good programming practice, since the data fields are not directly accessible out side the class. We must use the set/get methods to access the data fields.
An example, which uses a set of set/get methods, is shown below.
//SET/GET methods
//Author: rajeshvs@msn.com
using System;
class MyClass
{
private int x;
public void SetX(int i)
{
x = i;
}
public int GetX()
{
return x;
}
}
class MyClient
{
public static void Main()
{
MyClass mc = new MyClass();
mc.SetX(10);
int xVal = mc.GetX();
Console.WriteLine(xVal);//Displays 10
}
}
But C# provides a built in mechanism called properties to do the above. In C#, properties are defined using the property declaration syntax. The general form of declaring a property is as follows.
<acces_modifier> <return_type> <property_name>
{
get
{
}
set
{
}
}
Where <access_modifier> can be private, public, protected or internal. The <return_type> can be any valid C# type. Note that the first part of the syntax looks quite similar to a field declaration and second part consists of a get accessor and a set accessor.
For example the above program can be modifies with a property X as follows.
class MyClass
{
private int x;
public int X
{
get
{
return x;
}
set
{
x = value;
}
}
}
The object of the class MyClass can access the property X as follows.
MyClass mc = new MyClass();
mc.X = 10; // calls set accessor of the property X, and pass 10 as value of the standard field
//‘value’. This is used for setting value for the data member x.
Console.WriteLine(mc.X);// displays 10. Calls the get accessor of the property X.
The complete program is shown below.
//C#: Property
//Author: rajeshvs@msn.com
using System;
class MyClass
{
private int x;
public int X
{
get
{
return x;
}
set
{
x = value;
}
}
}
class MyClient
{
public static void Main()
{
MyClass mc = new MyClass();
mc.X = 10;
int xVal = mc.X;
Console.WriteLine(xVal);//Displays 10
}
}
Remember that a property should have at least one accessor, either set or get. The set accessor has a free variable available in it called value, which gets created automatically by the compiler. We can’t declare any variable with the name value inside the set accessor.
We can do very complicated calculations inside the set or get accessor. Even they can throw exceptions.
Since normal data fields and properties are stored in the same memory space, in C#, it is not possible to declare a field and property with the same name.
Static Properties
C# also supports static properties, which belongs to the class rather than to the objects of the class. All the rules applicable to a static member are applicable to static properties also.
The following program shows a class with a static property.
//C# : static Property
//Author: rajeshvs@msn.com
using System;
class MyClass
{
private static int x;
public static int X
{
get
{
return x;
}
set
{
x = value;
}
}
}
class MyClient
{
public static void Main()
{
MyClass.X = 10;
int xVal = MyClass.X;
Console.WriteLine(xVal);//Displays 10
}
}
Remember that set/get accessor of static property can access only other static members of the class. Also static properties are invoking by using the class name.
Properties & Inheritance
The properties of a Base class can be inherited to a Derived class.
//C# : Property : Inheritance
//Author: rajeshvs@msn.com
using System;
class Base
{
public int X
{
get
{
Console.Write("Base GET");
return 10;
}
set
{
Console.Write("Base SET");
}
}
}
class Derived : Base
{
}
class MyClient
{
public static void Main()
{
Derived d1 = new Derived();
d1.X = 10;
Console.WriteLine(d1.X);//Displays 'Base SET Base GET 10'
}
}
The above program is very straightforward. The inheritance of properties is just like inheritance any other member.
Properties & Polymorphism
A Base class property can be polymorphicaly overridden in a Derived class. But remember that the modifiers like virtual, override etc are using at property level, not at accessor level.
//C# : Property : Polymorphism
//Author: rajeshvs@msn.com
using System;
class Base
{
public virtual int X
{
get
{
Console.Write("Base GET");
return 10;
}
set
{
Console.Write("Base SET");
}
}
}
class Derived : Base
{
public override int X
{
get
{
Console.Write("Derived GET");
return 10;
}
set
{
Console.Write("Derived SET");
}
}
}
class MyClient
{
public static void Main()
{
Base b1 = new Derived();
b1.X = 10;
Console.WriteLine(b1.X);//Displays 'Derived SET Derived GET 10'
}
}
Abstract Properties
A property inside a class can be declared as abstract by using the keyword abstract. Remember that an abstract property in a class carries no code at all. The get/set accessors are simply represented with a semicolon. In the derived class we must implement both set and get assessors.
If the abstract class contains only set accessor, we can implement only set in the derived class.
The following program shows an abstract property in action.
//C# : Property : Abstract
//Author: rajeshvs@msn.com
using System;
abstract class Abstract
{
public abstract int X
{
get;
set;
}
}
class Concrete : Abstract
{
public override int X
{
get
{
Console.Write(" GET");
return 10;
}
set
{
Console.Write(" SET");
}
}
}
class MyClient
{
public static void Main()
{
Concrete c1 = new Concrete();
c1.X = 10;
Console.WriteLine(c1.X);//Displays 'SET GET 10'
}
}
The properties are an important features added in language level inside C#. They are very useful in GUI programming. Remember that the compiler actually generates the appropriate getter and setter methods when it parses the C# property syntax.
| DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware. |
More C# Articles
More By Rajesh V S
 developerWorks - FREE Tools!
|
You probably have thousands of lines of COBOL code loaded with business intelligence and being used to run your business, along with an army of developers maintaining these applications. Learn how to prepare your applications and developers so you can keep that competitive edge and move to a service-oriented architecture with the IBM Rational Enterprise Modernization solutions. Replay is available for 9 months.
FREE! Go There Now!
|
|
|
|
Build secure Web services with transport-level security using IBM Rational Application Developer V7 and IBM WebSphere Application Server V6.1. Follow this three-part series for step-by-step instructions about how to develop Web services and clients, configure HTTP basic authentication, and configure HTTP over SSL (HTTPS). This first part of the series walks you through building a Web service for a simple calculator application. You generate and test two different types of Web services clients: a Java Platform, Enterprise Edition (Java EE) client and a stand-alone Java client. You also handle user-defined exceptions in Web services.
FREE! Go There Now!
|
|
|
|
Visit IBM developerWorks to download a free trial of the latest release of IBM Lotus Sametime Standard V8.0. Lotus Sametime Standard V8.0 is a platform for unified communications and collaboration that combines security features with an extensible, open solution including integrated Voice over IP, geographic location awareness, mobile clients, and a robust Business Partner community offering telephony and video integration.
FREE! Go There Now!
|
|
|
|
Join us for this web seminar to learn how you can defend your web applications from attack. Learn about the 3 most common web application attacks, including how they occur and what can be done to prevent them. We’ll also discuss manual versus automated approaches for scanning and identifying web application vulnerabilities and how IBM Rational AppScan, an automated vulnerability scanner, can help you automate more of what you are doing manually today.
FREE! Go There Now!
|
|
|
|
Join this webcast to see how IBM Data Studio Developer and pureQuery can take the pain out of Java data access. uApplications developed using both Java and SQL have become a common requirement. Database connectivity using Java Database Connectivity (JDBC) to create an application is a multi-step tedious process, and tooling that covers both SQL and Java has been unavailable, until now. IBM Data Studio introduces the pureQuery platform: a high-performance, Java data access platform focused on simplifying the tasks of developing, managing, and optimizing database applications and services.
FREE! Go There Now!
|
|
|
|
IBM Enterprise Modernization solutions help organizations evolve core IT systems towards modern architectures and technologies—reducing the burden of maintenance and freeing up resources to develop new business requirements and capabilities. With the IBM Enterprise Modernization Sandbox for System z you can evaluate IBM Enterprise Modernization solutions focused on five key areas: Assets, Architectures, Skills, Processes and Infrastructures, and Investment. Each solution is based upon real customer experiences and offers a proven path to get you started with your modernization projects.
FREE! Go There Now!
|
|
|
|
Analysts, architects, and developers who have existing COBOL or PL/I skills and want to extend those skills to deploy new workloads on the mainframe can use the IBM Enterprise Modernization Sandbox for System z to find hands-on walkthroughs of common real world scenarios. The scenarios provide examples of how to rapidly design, create, assemble, test, and deploy high-quality Web, Web services, portal, and SOA applications for IBM CICS, IBM IMS, and IBM WebSphere Application Server.
FREE! Go There Now!
|
|
|
|
As systems increase in complexity, communication between systems and software teams becomes more and more difficult. Now, there’s a way to improve product quality and communication.<br />Read the “Model Driven Systems Development” white paper to see how. Also included in this kit are more educational white papers, customer examples, tutorials, informative Webcasts, and best practices for designing, building and managing systems.<br />
FREE! Go There Now!
|
|
|
|
Get a free trial download of the latest version of IBM Rational Performance Tester V7.0.1, a load and performance testing solution for teams concerned about the scalability of their Web-based applications. Combining multiple ease-of-use features with granular detail, Rational Performance Tester simplifies the test-creation, load-generation and data-collection processes that help teams ensure the ability of their applications to accommodate required user loads.
FREE! Go There Now!
|
|
|
|
Whether you are creating new applications or modifying existing ones, managing integration of new components with traditional z/OS elements is a critical part of building and deploying modern applications. Listen to this webcast to see how IBM can help you optimize your development process using an IDE like Rational Developer for System z that integrates with management tools, such as ClearCase to manage your application development on mainframes.
FREE! Go There Now!
|
|
|
|
All FREE IBM® developerWorks Tools!
|
/ 31 
