C# - 12 Properties

Properties in C# 12 

C# 12 introduces extended features for properties to enhance code flexibility, readability, and functionality. Here are the new or improved property-related features in C# 12:

1.  Primary Constructors and Initializer Syntax

C# 12 allows the declaration of properties directly in the primary constructor of a class or struct. This reduces boilerplate code.

public class Employee(string Name, int Age)
{
    public string Role { get; set; } = "Developer"; // Additional property
}

Usage

var emp = new Employee("Alice", 30);
Console.WriteLine($"{emp.Name}, {emp.Age}, {emp.Role}");

• 
  The properties Name and Age are automatically created with public get and init.
• You can add other properties (Role) as needed.

2. Default Values in Primary Constructor Properties

You can now assign default values directly in primary constructor properties.

public class Product(string Name = "Unknown", decimal Price = 0.0m)
{
    public string Category { get; set; } = "General";
}

Usage

var product = new Product();
Console.WriteLine($"{product.Name}, {product.Price}, {product.Category}");
// Output: Unknown, 0.0, General

3. Collection Expressions for Properties

C# 12 introduces collection expressions, which can be used for property initialization. This simplifies complex object initialization.

public class Order
{
    public List<string> Items { get; set; } = ["Item1", "Item2", "Item3"];
}

//Usage
var order = new Order();
Console.WriteLine(string.Join(", ", order.Items)); // Output: Item1, Item2, Item3

4. Property Patterns for Matching

With property patterns in C# 12, you can use the new and operator in pattern matching to enforce conditions across multiple properties.

Code

public class Employee
{
    public string Name { get; set; }
    public int Age { get; set; }
}

bool IsValidEmployee(Employee emp) => emp is { Name.Length: > 3, Age: >= 18 and <= 65 };


//Usage
var emp = new Employee { Name = "Alice", Age = 25 };
Console.WriteLine(IsValidEmployee(emp)); // Output: True

5. Init-Only Properties (Enhanced with Primary Constructors)

C# 12 enhances init-only properties by integrating them with primary constructors, making objects more immutable while maintaining flexibility during initialization.

public class Customer(string Name, string Email)
{
    public string Address { get; init; }
}

//usage
var customer = new Customer("John", "john@example.com") { Address = "123 Main St" };
Console.WriteLine(customer.Address); // Output: 123 Main St