using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/53656430/how-to-parse-string-to-datetime-with-a-m-or-p-m-format

​

    class TestClass

    {

        public static void Test()

        {

            var testStrings =  new [] { "6/12/2018  12:00:03 a. m.", "6/12/2018  12:00:03 p. m." };

            foreach (var date in testStrings)

            {

                Console.WriteLine("\nInput date string: {0}", date);

                // Construct an invariant DateTimeFormatInfo and modify its AMDesignator and PMDesignator.

                // The DateTimeFormat must be cloned since the global instance is read-only.

                var formatInfo = (DateTimeFormatInfo)CultureInfo.InvariantCulture.DateTimeFormat.Clone();

                formatInfo.AMDesignator = "a. m.";

                formatInfo.PMDesignator = "p. m.";

​

                var x = DateTime.ParseExact(date, "d/MM/yyyy  h:mm:ss tt", formatInfo);

​

                Console.WriteLine(x);

                Console.WriteLine(x.ToUniversalTime().ToString("yyyy-MM-ddTHH\\:mm\\:ss.fffffffzzz"));

​

                Console.WriteLine(x.ToString("d/MM/yyyy  h:mm:ss tt", formatInfo));

                try

                {

                    var x2 = Convert.ToDateTime(date);

​

                    Console.WriteLine("Result of  Convert.ToDateTime(date):");

                    Console.WriteLine(x2.ToUniversalTime().ToString("yyyy-MM-ddTHH\\:mm\\:ss.fffffffzzz"));

                }

                catch (Exception ex)

                {

                    Console.WriteLine("Unable to parse this string with Convert.ToDateTime(date), error = " + ex.Message);

                }

            }

            Console.WriteLine();

            foreach (var info in CultureInfo.GetCultures(CultureTypes.AllCultures))

            {

                if (info.DateTimeFormat.AMDesignator == "a. m." && info.DateTimeFormat.PMDesignator == "p. m.")

                {

                    Console.WriteLine("Culture {0} ({1}) has the required AM and PM designators.", info.DisplayName, info.Name);

                }

            }

            foreach (var date in testStrings)

            {

                var formatInfo = CultureInfo.GetCultureInfo("es-MX");

                var x = DateTime.ParseExact(date, "d/MM/yyyy  h:mm:ss tt", formatInfo);

                Console.WriteLine("\nInput date string: {0} parsed using {1}:", date, formatInfo);

​

                Console.WriteLine(x);

                Console.WriteLine(x.ToUniversalTime().ToString("yyyy-MM-ddTHH\\:mm\\:ss.fffffffzzz"));

​

                Console.WriteLine(x.ToString("d/MM/yyyy  h:mm:ss tt", formatInfo));

            }

        }   

        static string GetJson()

        {

            var json = @"

";

            return json;

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: " + Environment.Version);

            Console.WriteLine("Json.NET version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​