Auto-properties
Learn auto-properties and assigning default values.
Auto-properties
Most of the time, a property's get and set bodies just return and write a private field. C# removes this boilerplate with an auto-property: public string Name { get; set; }.
The compiler generates a hidden field behind the scenes; you write no private field. Shorter, more readable. When you need validation, you can switch back to an explicit body; the interface does not change. Most properties in modern C# code are written as auto-properties.
Default values
You can give an auto-property a default value with an equals sign: public int Count { get; set; } = 0; or public string Label { get; set; } = "New";.
This value is assigned automatically when the object is created; no constructor is needed. Read-only auto-properties can also take a default: public string Code { get; } = "A100";. This is useful for values set at creation and never changed afterwards.
Exercise Add auto-properties to the Product class
Define a Product class. Add public string Name { get; set; } and public int Stock { get; set; } = 0; auto-properties. Inside Main create an instance with new Product { Name = "Pen" } and print Name and Stock.
Show example solution
Add two auto-properties to Product. In Main write Product p = new Product { Name = "Pen" }; Console.WriteLine(p.Name); Console.WriteLine(p.Stock);
Example solution:
using System;
class Product
{
public string Name { get; set; }
public int Stock { get; set; } = 0;
}
class Program
{
static void Main()
{
Product p = new Product { Name = "Pen" };
Console.WriteLine(p.Name);
Console.WriteLine(p.Stock);
}
}Test yourself
-
Match each declaration to its type
- { get; set; }
- Auto-property
- { get; }
- Read-only auto
- { get; set; } = 5;
- With default value
- private string name;
- Field
-
Complete the auto-property
public string Name { get; ____; }Show answer
public string Name { get; set; } -
Which is an auto-property with default value 5?
- public int Count { get; set; }
- public int Count = 5;
- public int Count() { return 5; }
- public int Count { get; set; } = 5;
Show answer
public int Count { get; set; } = 5; — Correct. = 5 gives the auto-property a default value.