Getters And Setters

Getters

Getters give public access to private data. They may also make a small modification of the returned result.

The syntax for defining getter is:

type name { get; }

Let's look the following example:

using System; namespace ConsoleApp1 { public class Square { // getter and default value for side; public double side { get; } = 4; } class Program { static void Main(string[] args) { Square square = new Square(); // usage of getter: double side = square.side; // square.side = 8; Console.WriteLine(side); } } }

Output:

4

Explanation:

• At line 8 a getter is defined and a default value is set for the class member side.
• If we uncomment line 20 the code won't compile. That's because a setter is not defined.

Setters

Setters allow for a private variable to be modified. They are important since they can provide validation before a value is set.

The syntax for defining setter is:

type name { set; }

Let's look at the following example:

using System; namespace ConsoleApp1 { class Person { public string name { get; set; } public int age { get; set; } public void printData() { Console.WriteLine("Name: " + name); Console.WriteLine("Age: " + age); } } class Program { static void Main(string[] args) { Person person = new Person(); person.name = "Emily"; person.age = 20; person.printData(); } } }

Output:

Name: Emily Age: 20

Explanation:

• At lines 7 and 8 members are defined with getter and setter.
• At line 22 and 23 the setters are used.

Customizing getters and setters

Via customization a getter may return a modification of the member and a setter may hold validation.

using System; namespace ConsoleApp1 { class Square { double _side; public double side { get { return Math.Round(_side, 2); } set { Console.WriteLine("Value to be set: " + value); if (value <= 0) { return; } this._side = value; } } public double calcArea() { return _side * _side; } } class Program { static void Main(string[] args) { Console.WriteLine("Square 1:"); Square square_1 = new Square(); square_1.side = 2.12345; // setter Console.WriteLine("Side = " + square_1.side);// getter Console.WriteLine("Area = " + square_1.calcArea()); Console.WriteLine("- - - - - -"); Console.WriteLine("Square 2:"); Square square_2 = new Square(); square_2.side = -1; // setter Console.WriteLine("Side = " + square_2.side); // getter } } }

Output:

Square 1: Value to be set: 2.12345 Side = 2,12 Area = 4.5090399025 - - - - - - Square 2: Value to be set: -1 Side = 0

Explanation:

• There are 2 members defined at line 7 and 8.
• There are getters and setters for side that access / modify _side.
• The getter returns the value rounded to two digits after decimal point (line 12).
• At the setter the value is validated. If validation fails the new value is not set (remains the default one - 0).
• The additional member _side is needed for both getter and setter. If line 24 is replaced with this.side = value; then an infinite recursion will be formed for the setter function.

Why using getters and setters?

Because members can have validation before modification (setter) and controlled access (getter).