C-9-Records.cs

void Main()
{
	// 1: NOT QUITE IMMUTABLE 
	var mutablePerson = new MutablePerson();
	mutablePerson.Name = "Clint";
	mutablePerson.Age = 41;
		
	mutablePerson.Dump("Initial Values");
	
	mutablePerson.Name = "Jerry";
	mutablePerson.Age = 32;
	
	mutablePerson.Dump("After change");
	
	
	
	
	// 2: GOTTA BE IMMUTABLE!!
	// COMPILATION ERROR - MUST INITIALISE USING PARAMETERISED CONSTRUCTOR
	// var immutablePerson = new ImmutablePerson();
	
	var immutablePerson = new ImmutablePerson("Jane", 28);
	immutablePerson.Dump("Immutable Shorthand");

	// COMPILATION ERROR - INIT ONLY PROPERTY CANNOT BE SET IN THIS CONTEXT
	// immutablePerson.Name = "Shiela";

	
	
	
	// 3: IMMUTABLE TOO
	// THIS IS OK - USE WHEN YOU NEED OBJECT INITIALIZER SYNTAX
	var immutableV2 = new ImmutablePersonV2() 
	{
		Name = "test",
		Age = 17
	};
	
	// COMPILATION ERROR - CANNOT ASSIGN INIT ONLY PROPERTY HERE
	//immutableV2.Name = "Change";
	immutableV2.Dump("Immutable object initializer syntax");
	
	
	
	// 4: CLONE AN IMMUTABLE, WITH CHANGES
	var iMaClone = immutableV2 with { Age = 22 };
	
	iMaClone.Dump("The Clone");
}

// You can define other methods, fields, classes and namespaces here
public record MutablePerson
{
	// Get and Set can be dropped without altering the behaviour
	public string Name { get; set; }
	public int Age { get; set; }
}

public record ImmutablePerson(string Name, int Age);

public record ImmutablePersonV2
{
	public string Name { get; init; }
	public int Age { get; init; }
}

/*
Error CS8852 Init-only property or indexer ‘{your property}’ can only be assigned in an object initializer, or on ‘this’ or ‘base’ in an instance constructor or an ‘init’ accessor.
*/

/*
REFERENCES
- Record Types: https://dotnetcoretutorials.com/2020/09/25/record-types-in-c-9/
- Using Immutable Options: https://anthonygiretti.com/2020/08/19/asp-net-core-5-make-your-options-immutable/
*/