.NET class to create and maintain vCalendar information

//$Date: 6/17/03 12:58p $
//$Revision: 1 $

using System;
using OnlineScorekeeper.Helpers;

namespace OnlineScorekeeper.Helpers
{
	public class vCalendar
	{
		//Specs can be found at: http://www.imc.org/pdi/pdiproddev.html
		public vEvents Events;

		public override string ToString()
		{
			System.Text.StringBuilder result = new System.Text.StringBuilder();
			result.AppendFormat("BEGIN:VCALENDAR{0}", System.Environment.NewLine);

			//The following two lines seem to be required by Outlook to get the alarm settings
			result.AppendFormat("VERSION:2.0{0}", System.Environment.NewLine);
			result.AppendFormat("METHOD:PUBLISH{0}", System.Environment.NewLine);

			result.Append(Events.ToString());
			result.AppendFormat("END:VCALENDAR{0}", System.Environment.NewLine);
			return result.ToString();
		}

		public vCalendar(vEvent value)
		{
			this.Events.Add(value);
		}

		public vCalendar()
		{
			//Do nothing
		}

		public class vRecurrence
		{
			//RRULE:FREQ=YEARLY;INTERVAL=1;BYMONTHDAY=12;BYMONTH=11;WKST=SU				//Every year on Nov 12
			//RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=TU;BYMONTH=11;BYSETPOS=2;WKST=SU		//Every 2nd Tue of Nov, yearly
			//RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=SA;BYMONTH=11;BYSETPOS=-1;WKST=SU		//Last Sat of Nov
			//RRULE:FREQ=YEARLY;INTERVAL=1;BYDAY=SA;BYMONTH=11;BYSETPOS=1;WKST=SU		//First Sat of Nov, yearly
			//RRULE:FREQ=WEEKLY;INTERVAL=2;BYDAY=SU,MO,TU,WE,TH,FR,SA;WKST=SU			//every 2 weeks on all days
			//RRULE:FREQ=DAILY; INTERVAL=1;UNTIL=20031110T000000Z;WKST=SU				//daily every 1 day until end date
			//RRULE:FREQ=DAILY; COUNT=10;INTERVAL=1;BYDAY=MO,TU,WE,TH,FR;WKST=SU			//daily every day for 10 occurrences

			public enum Frequencies
			{
				Daily, Weekly, Monthly, Yearly
			}

			public enum DaysOfWeek
			{
				Su, Mo, Tu, We, Th, Fr, Sa
			}

			public Frequencies Frequency;
			public int Interval = 0;
			public DaysOfWeek WeekStart = DaysOfWeek.Su;
			public DateTime EndDateTime;
			public int Occurences = 0;

			private int m_MonthDay;

			public int MonthDay
			{
				get { return m_MonthDay; }
				set
				{
					if (value >= 1 || value <= 31)
					{
						m_MonthDay = value;
					}
					else
					{
						throw new Exception("MonthDay must be between 1 and 31.");
					}
				}
			}

			public override string ToString()
			{
				System.Text.StringBuilder result = new System.Text.StringBuilder();
				result.Append("RRULE:");
				result.AppendFormat("FREQ={0};", Frequency.ToString().ToUpper());
				if (Interval > 0)
					result.AppendFormat("INTERVAL={0};", Interval);
				if (EndDateTime > DateTime.MinValue)
					result.AppendFormat("UNTIL={0};", EndDateTime.ToUniversalTime().ToString("yyyyMMdd\\THHmmss\\Z"));
				if (Occurences > 0)
					result.AppendFormat("COUNT={0};", Occurences);
				result.AppendFormat("WKST={0}", WeekStart.ToString().ToUpper());
				return (result.ToString());
			}
		}

		public class vAlarm
		{
			public TimeSpan Trigger;	//Amount of time before event to display alarm
			public string Action;		//Action to take to notify user of alarm
			public string Description;	//Description of the alarm

			public vAlarm()
			{
				Trigger = TimeSpan.FromDays(1);
				Action = "DISPLAY";
				Description = "Reminder";
			}

			public vAlarm(TimeSpan setTrigger)
			{
				Trigger = setTrigger;
				Action = "DISPLAY";
				Description = "Reminder";
			}

			public vAlarm(TimeSpan setTrigger, string setAction, string setDescription)
			{
				Trigger = setTrigger;
				Action = setAction;
				Description = setDescription;
			}

			public override string ToString()
			{
				System.Text.StringBuilder result = new System.Text.StringBuilder();
				result.AppendFormat("BEGIN:VALARM{0}", System.Environment.NewLine);
				result.AppendFormat("TRIGGER:P{0}DT{1}H{2}M{3}", Trigger.Days, Trigger.Hours, Trigger.Minutes, System.Environment.NewLine);
				result.AppendFormat("ACTION:{0}{1}", Action, System.Environment.NewLine);
				result.AppendFormat("DESCRIPTION:{0}{1}", Description, System.Environment.NewLine);
				result.AppendFormat("END:VALARM{0}", System.Environment.NewLine);
				return result.ToString();
			}
		}

		public class vEvent
		{
			public string UID;						//Unique identifier for the event
			public DateTime DTStart;				//Start date of event.  Will be automatically converted to GMT
			public DateTime DTEnd;					//End date of event.  Will be automatically converted to GMT
			public DateTime DTStamp;				//Timestamp.  Will be automatically converted to GMT
			public string Summary;					//Summary/voidject of event
			public string Organizer;				//Can be mailto:, url, or just a name
			public string Location;					//Location of event
			public string Description;				//Description of event
			public string url;						//URL for event info
			public vAlarms Alarms = new vAlarms();	//Alarms for this event
			public vRecurrence Recurrence;
			public bool isPrivate = false;

			public override string ToString()
			{
				System.Text.StringBuilder result = new System.Text.StringBuilder();
				result.AppendFormat("BEGIN:VEVENT{0}", System.Environment.NewLine);
				result.AppendFormat("UID:{0}{1}", UID, System.Environment.NewLine);
				result.AppendFormat("SUMMARY:{0}{1}", Summary, System.Environment.NewLine);
				result.AppendFormat("ORGANIZER:{0}{1}", Organizer, System.Environment.NewLine);
				result.AppendFormat("LOCATION:{0}{1}", Location, System.Environment.NewLine);
				result.AppendFormat("DTSTART:{0}{1}", DTStart.ToUniversalTime().ToString("yyyyMMdd\\THHmmss\\Z"), System.Environment.NewLine);
				result.AppendFormat("DTEND:{0}{1}", DTEnd.ToUniversalTime().ToString("yyyyMMdd\\THHmmss\\Z"), System.Environment.NewLine);
				if (Recurrence != null) result.Append(Recurrence.ToString());
				result.AppendFormat("DTSTAMP:{0}{1}", DateTime.Now.ToUniversalTime().ToString("yyyyMMdd\\THHmmss\\Z"), System.Environment.NewLine);
				result.AppendFormat("DESCRIPTION:{0}{1}", Description, System.Environment.NewLine);
				if (!Strings.IsBlank(url)) result.AppendFormat("URL:{0}{1}", url, System.Environment.NewLine);
				result.Append(Alarms.ToString());
				if (isPrivate)
					result.AppendFormat("CLASS:{0}{1}", "PRIVATE", System.Environment.NewLine);
				else
					result.AppendFormat("CLASS:{0}{1}", "PUBLIC", System.Environment.NewLine);

				result.AppendFormat("END:VEVENT{0}", System.Environment.NewLine);
				return result.ToString();
			}
		}

		public class vAlarms : System.Collections.CollectionBase
		{

			public vAlarm Add(vAlarm value)
			{
				// After you inherit the CollectionBase class, you can access an intrinsic object
				// called InnerList that represents your collection. InnerList is of type ArrayList.
				this.InnerList.Add(value);
				return (value);
			}

			public vAlarm Item(int index)
			{
				// To retrieve an item from the InnerList, pass the index of that item to the .Item property.
				return (vAlarm) this.InnerList[index];
			}

			public void Remove(int index)
			{
				// This Remove expects an index.
				vAlarm cust = (vAlarm) this.InnerList[index];
				if (cust != null)
					this.InnerList.Remove(cust);
			}

			public override string ToString()
			{
				System.Text.StringBuilder result = new System.Text.StringBuilder();
				foreach(vAlarm item in this.InnerList)
				{
					result.Append(item.ToString());
				}
				return (result.ToString());
			}
		}

		public class vEvents : System.Collections.CollectionBase
		{

			public vEvent Add(vEvent value)
			{
				// After you inherit the CollectionBase class, you can access an intrinsic object
				// called InnerList that represents your collection. InnerList is of type ArrayList.
				this.InnerList.Add(value);
				return value;
			}

			public vEvent Item(int index)
			{
				// To retrieve an item from the InnerList, pass the index of that item to the .Item property.
				return (vEvent) this.InnerList[index];
			}

			public void Remove(int index)
			{
				// This Remove expects an index.
				vEvent cust = (vEvent) this.InnerList[index];
				if (cust != null)
					this.InnerList.Remove(cust);
			}

			public override string ToString()
			{
				System.Text.StringBuilder result = new System.Text.StringBuilder();
				foreach(vEvent item in this.InnerList)
				{
					result.Append(item.ToString());
				}
				return (result.ToString());
			}
		}
	}
}

Private Sub Page_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
    Response.Clear()
    Dim EventID As Integer = 777
    Dim EventName As String = "BBQ"
    Response.AddHeader("Content-Disposition", "filename=EventID" + EventID.ToString + ".ics")
    Dim evt As New vCalendar.vEvent()
    evt.UID = "EventID" + EventID.ToString
    evt.DTStart = DateTime.Now
    evt.DTEnd = evt.DTStart.AddHours(1)
    evt.Summary = "Event: " + EventName
    evt.URL = Me.AppRootURL() + "/EventInfo.aspx?EventID=" + EventID.ToString
    evt.Description = "View event online: " + evt.URL
    Dim FacilityName As String = "Lopez Lake"
    Dim FacilityDescription As String = "1234 Lopez Lake Drive, San Luis Obispo, CA 93401"
    Dim Location As String = FacilityName + " - " + FacilityDescription
    evt.Location = Location
    evt.Organizer = "Me"
    evt.Alarms.Add(New vCalendar.vAlarm(TimeSpan.FromDays(1)))
    Dim cal As New vCalendar(evt)
    Response.Write(cal.ToString())
    Response.End()
End Sub