Properties (get/set)

Syntax

public Type PropertyName { get; set; }

Examples

public class Person
{
    public string Name { get; set; } = "";
    public int Age { get; set; }
}

Person p = new Person();
p.Name = "Fola";
p.Age = 21;

Console.WriteLine($"{p.Name} is {p.Age}");

public class Product
{
    private double _price;

    public double Price
    {
        get => _price;
        set
        {
            if (value < 0)
                throw new ArgumentException("Price cannot be negative");
            _price = value;
        }
    }
}

Product item = new Product();
item.Price = 25;
Console.WriteLine(item.Price);  // 25

try
{
    item.Price = -10;  // throws
}
catch (ArgumentException e)
{
    Console.WriteLine(e.Message);
}

public class Circle
{
    public double Radius { get; }  // set only in the constructor

    public Circle(double radius)
    {
        Radius = radius;
    }

    public double Area => Math.PI * Radius * Radius;  // computed, expression-bodied
}

Circle c = new Circle(5);
Console.WriteLine(c.Area);  // 78.5398...
// c.Radius = 10;  // Error - no setter available

public class Order
{
    public string Id { get; init; } = "";
    public double Total { get; init; }
}

Order order = new Order { Id = "ORD-1", Total = 49.99 };
Console.WriteLine($"{order.Id}: {order.Total}");

// order.Total = 100;  // Error - init-only, can't change after creation

Best practices

• Use auto-implemented properties ({ get; set; }) by default, and switch to a full property with a backing field only when you need validation or computed logic
• Use { get; } (or init) instead of { get; set; } for values that should never change after an object is created
• Prefer properties over public fields for anything exposed outside the class - it keeps the door open to add logic later without breaking existing callers
• Use expression-bodied properties (=> expression) for simple computed values to keep the class concise

At a glance

Purpose

Applications on the .NET platform

File extension

.cs

Runs in

.NET runtime

Usually used with

.NET SDK and libraries

Specifications & further reading

• C# language reference

Related C# documentation