using System;

using System.Text.RegularExpressions;

public class Program

{

    public static void Main()

    {

        string Test = "26/3/2021";

        Console.WriteLine(Convert.ToDateTime(Test.convertDate()));

​

    }

}

​

    public static class StringExtensions

    {

        public static DateTime convertDate(this string text)

        {

            //Console.WriteLine(text);  

            DateTime parsedDate;

            Regex pattern = new Regex("^(.*?) ", RegexOptions.Compiled);

            Match match = pattern.Match(text); 

            if (match.Success)

            {

                text = ((match.ToString()).Trim()); 

            }       

            string[] subs = text.Split(' ', '/');

            string newValue;

            string M = subs[1];

            string d = subs[0];

            string Y = subs[2];

            if(M.Length == 1)

                {

                    M = string.Concat("0",M);

                }

            if(d.Length == 1)

                {

                    d = string.Concat("0",d);

                }

            newValue = string.Concat(Y, "-", M, "-", d);

​

            Console.WriteLine(newValue);

​

            parsedDate = Convert.ToDateTime(newValue);

            return parsedDate;

        }

    }

​