ICS calendar item creation

// Title:  ICS calendar item creation
// Author: Emily Heiner
// Date:   2016-12-08
// This code is licensed under the Creative Commons Attribution-ShareAlike 3.0 Unported license.
// You are free to share and adapt this code for any purposes, commerical and non-commercial,
// as long as appropriate credit is given, you indicate if changes were made, and you share your
// modified code. License details can be found at https://creativecommons.org/licenses/by-sa/3.0/

using System;

namespace ESH.Utility
{
    public static class Email
    {
        /// <summary>
        /// Creates an ICS calendar item
        /// </summary>
        /// <param name="startDate">Calendar item Start Date/Time</param>
        /// <param name="endDate">Calendar item End Date/Time</param>
        /// <param name="summary">Calendar item summary</param>
        /// <param name="location">Calendar item Location</param>
        /// <param name="notificationTime">Notification time examples: "30M" (30 Minutes), "1H" (1 Hour), "24H" (24 Hours)</param>
        /// <returns>String containing the ICS calendar item</returns>
        public static string CreateICS(DateTime startDate, DateTime endDate, string summary, string location, string notificationTime)
        {
            string ics = "";
            ics += "BEGIN:VCALENDAR" + Environment.NewLine;
            ics += "VERSION:2.0" + Environment.NewLine;
            ics += "PRODID:-//hacksw/handcal//NONSGML v1.0//EN" + Environment.NewLine;
            ics += "BEGIN:VEVENT" + Environment.NewLine;
            ics += "UID:" + Guid.NewGuid() + Environment.NewLine;
            ics += "DSTAMP;TZID=/US/Pacific:" + ConvertToICSDateTime(DateTime.Now) + Environment.NewLine;
            ics += "DTSTART;TZID=/US/Pacific:" + ConvertToICSDateTime(startDate) + Environment.NewLine;
            ics += "DTEND;TZID=/US/Pacific:" + ConvertToICSDateTime(endDate) + Environment.NewLine;
            ics += "SUMMARY:" + summary + Environment.NewLine;
            ics += "LOCATION:" + location + Environment.NewLine;
            if (notificationTime != null)
            {
                ics += "BEGIN:VALARM" + Environment.NewLine;
                //Notification time examples: 30M (30 Minutes), 1H (1 Hour), 24H (24 Hours)
                ics += "TRIGGER:-PT" + notificationTime + Environment.NewLine;
                ics += "ACTION:DISPLAY" + Environment.NewLine;
                ics += "END:VALARM" + Environment.NewLine;
            }
            ics += "END:VEVENT" + Environment.NewLine;
            ics += "END:VCALENDAR" + Environment.NewLine;

            return ics;
        }

        /// <summary>
        /// Converts a DateTime object into an ICS date/time string
        /// </summary>
        /// <param name="input">DateTime object to convert</param>
        /// <returns>ICS date/time string</returns>
        public static string ConvertToICSDateTime(DateTime input)
        {
            return input.ToString("yyyyMMddTHmmss");
        }
    }
}