C# Properties

10 Questions

What is the purpose of declaring a field as static in a class?

To share a single variable among all members of the class

What is the difference between a static field and a non-static field?

A static field is shared by all members, while a non-static field is specific to each instance

What is the purpose of declaring a method as static in a class?

To make the method independent of a particular object

What is the correct way to call a static method?

Using the class name

What is the purpose of declaring a field as const in a class?

To ensure that the field cannot be changed

What is the difference between a static method and a non-static method?

A static method is independent of a particular object, while a non-static method is not

Can a method parameter be declared as static?

No, it is not possible to declare a method parameter as static

What is the purpose of the Main method in a C# program?

To serve as the starting point for the program

What is the difference between a static variable and a non-static variable?

A static variable is shared by all members, while a non-static variable is specific to each instance

Why are static methods similar to functions in a procedural language?

Because they operate on values passed as arguments, without needing any data from the class

Study Notes

Properties

A property is a member that provides a flexible mechanism to read, write, or compute the value of a private field.
Properties can be read-write, read-only, or write-only.
The set accessor takes a single implicit parameter named value but does not return any value.
Example: public int Age { set { age = value; } get { return age; }

Read-only and Write-Only Properties

get or set can be omitted to create a read-only or write-only property.
Example: public long Balance { get { return balance; } }

Benefits of Properties

Allow read-only and write-only fields.
Can validate a field when it is accessed.
Can substitute for fields in interfaces.

Static Members

Static members are accessed by the class name, not the instance name.
Non-static class should also define a static constructor if the class contains static members.

Static Constructors

A static constructor is a special constructor that gets called before the first object of the class is created.
It is used to initialize any static data, or to perform a particular action that needs performed once only.
Rules for static constructors:
- A class can have only one static constructor (no constructor overloading)
- Static constructor can not have any parameter
- Static constructor can not have any access specifier
Example: static class T { static int id; static T() { id = 0; } }

Static Constructor in Non-Static Class

The compiler will provide the default parameterless constructor.
A static constructor needs its class’ fields and properties to be static also to be able to initialize them.

Readonly Fields

The readonly keyword is a modifier that can be used on fields.
When a field declaration includes a readonly modifier, assignments to the fields introduced by the declaration can only occur as part of the declaration or in a constructor in the same class.

Static Fields

Static fields are shared by all members of a class and are independent of any instances.
Declare the field static to make it a static field.
Non-static field is called an instance field.
Example: public static double PI = 3.14159265358979;

Static Methods

Static methods are similar to functions in a procedural language.
Static methods don’t need any data from the class and operate on values passed as arguments.
Method parameters/variables can’t be static.
Example: public static double Sqrt(double d) { ... }