using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Setting Nullable Date Field");

        var record = new Employee();

        Console.WriteLine($"Default Nullable DateTime Value: {record.Dob}, record.Dob.HasValue? {record.Dob.HasValue}");

        record = new Employee()

        {

            Dob = new DateTime()

        };

        Console.WriteLine($"Default Nullable DateTime Value: {record.Dob}, record.Dob.HasValue? {record.Dob.HasValue}");

        /* 

            Values to parse

            "2000-07-04"

            ""

            string.Empty

            null

        */

        List<string> tests =new List<string>();

        tests.Add("2000-07-04");    // 1

        tests.Add("");              // 2

        tests.Add(string.Empty);    // 3

        tests.Add(null);            // 4

        // Code with a bug

        for(int i = 0; i < tests.Count; i++)

        {

            try

            {

                string dateString = tests[i];

​

                record = new Employee();

​

                record.Dob = DateTime.Parse(dateString);

​

                Console.WriteLine($"Read DateTime Value: { record.Dob }");

            }

            catch (Exception ex)

            {

                Console.WriteLine($"Test #{i+1} doesn't work.");

                Console.WriteLine(ex.Message);

            }

        }

        // bug fix

        foreach (var test in tests)

        {

            string dateString = test;

            record = new Employee();

            DateTime birthDate;

            if (DateTime.TryParse(dateString, out birthDate))

            {

                record.Dob = birthDate;

            }

            Console.WriteLine($"Read DateTime Value: { record.Dob }");

        }

    }

    public class Employee 

    {       

        public DateTime? Dob {get;set;}

    }

}