A quick example of showing how to add a Deconstruct method using Extensions for existing built-in types

_Program.cs

using System;


public class Program
{
    public static void Main()
    {
        
        //  Calls the Deconstruct(DateTime, int, int, int) method we created in
        //  the DateTimeExtensions class.
        var (day, month, year) = DateTime.Now;

        //  Output to show results.
        Console.WriteLine($"{day}/{month}/{year}");
        Console.ReadLine();
    }
}

DateTimeExtensions.cs

/// <summary>
///     Extension class for DateTime objects that adds a Deconstruct method for DateTime
/// </summary>
public static class DateTimeExtensions
{
    /// <summary>
    ///     Deconstructs a DateTime instance into day, month, and year ints.
    /// </summary>
    /// <param name="dateTime">The DateTime instance</param>
    /// <param name="day">The day</param>
    /// <param name="month">The month</param>
    /// <param name="year">The year</param>
    public static void Deconstruct(this DateTime dateTime, out int day, out int month, out int year)
    {
        day = dateTime.Day;
        month = dateTime.Month;
        year = dateTime.Year;
    }
}