Record Type in C#

 Record type

Record can be class or struct.

Class is default and it need not be defined.

public record class Person(string FullName, DateOnly DateOfBirth);

equivalent to saying

public class Person{

public string FullName {get; init;} = default!;

public DateOnly DateOfBirth {get; set;}

}

public record struct Person(string FullName, DateOnly DateOfBirth);

Console.WriteLine(new Person{ FullName = "Kirthiga", DateOfBirth = new DateOnly(1996, 8, 7)};

It will say NameSpace.Person but won't say the details

var kirthiga = new Person("Kirthiga", new DateOnly(1996,8,7));

On the other hand when you use record and do a Console.WriteLine(kirthiga);

It will print out Person {FullName = "Kirthiga", DateOfBirth = "07/08/1996"} with full details

Also when we duplicate classes example,

var personA = new Person{

FullName = "Kirthiga",

DateOfBirth = "07/08/1996"

} 

var personB = new Person{

FullName = "Kirthiga",

DateOfBirth = "07/08/1996"

} 

Console.WriteLine(personA == personB); // will return false and it is comparing reference type.

But in case of records this will be true if they have the same properties.

Console.WriteLine(kirthiga1 == kirthiga2); // return true if you want to check reference

go for 

Console.WriteLine(ReferenceEquals(kirthiga1, kirthiga2)); // return false

Kirthiga's twin

var mithila = kirthiga with {FullName = "mithila"};

Console.WriteLine(mithila);

Deconstructor

var (name, dateOfBirth) = mithila;

Console.WriteLine(name);

Console.WriteLine(dateOfBirth);

The properties are deconstructed.

The value of a record is immutable as we have init in props

public record Person(string FullName, DateOnly DateOfBirth)

    {

        protected virtual bool PrintMembers(StringBuilder builder)

        {

            builder.Append($"FullName is : {FullName} and the dateofBirth is : {DateOfBirth}");

            return true;

        }

    }

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public void Deconstruct(out string FullName, out DateOnly DateOfBirth)

    {

        FullName = this.FullName;

        DateOfBirth = this.DateOfBirth;

    }

Also can be easily serialised and deserialised.

using System.Text.Json;

jsonString = JsonSerializer.Serialize(kirthiga);

Console.WriteLine(jsonString);

var recKirthiga = JsonSerializer.Deserialize(jsonString);

Console.WriteLine(recKirthiga); 

Will use the PrintMembers

The virtual keyword is used to modify a method, property, indexer, or event declaration and allow for it to be overridden in a derived class.