iCal client support for multiple event requests

Question

When a user signs up on our website, I'd like to send them an email that allows them to automatically update their calendar with the classes they have enrolled in. In most cases this will be multiple days/events.

As a test I'm using DDay.ical to create a multi-event request. However, it doesn't seem like either Outlook or the iPhone mail app notices the second event in the ical attachment.

I know that multiple events are supported in the iCal standard. How that doesn't mean that all clients support that scenarios. Do other clients support multi-event ical requests?

I don't think I'm doing anything wrong in code, but I'll post my code fragment to be sure:

                    // Create event part.
                iCalendar iCal1 = new iCalendar();
                iCal1.AddLocalTimeZone();

                iCal1.Method = "REQUEST";

                Event evt1 = iCal1.Create<Event>();
                evt1.Start = new iCalDateTime(new DateTime(2014, 8, 4, 12, 30, 00, DateTimeKind.Local));
                evt1.End = evt1.Start.AddMinutes(30);
                evt1.IsAllDay = false;
                evt1.Summary = string.Format("Lesson - {0}", evt1.Start.ToString("MM/dd"));
                evt1.Location = "Anytown";

                // Add recipients for appointment.
                Attendee att1 = new Attendee("mailto:" + "[email protected]");
                att1.RSVP = false;
                att1.CommonName = "Me Jones";
                evt1.Attendees.Add(att1);


                Event evt2 = iCal1.Create<Event>();
                evt2.Start = new iCalDateTime(new DateTime(2014, 8, 11, 12, 30, 00, DateTimeKind.Local));
                evt2.End = evt1.Start.AddMinutes(30);
                evt2.IsAllDay = false;
                evt2.Summary = string.Format("Lesson - {0}", evt2.Start.ToString("MM/dd"));
                evt2.Location = "AnyTown";

                // Add recipients for appointment.
                Attendee att2 = new Attendee("mailto:" + "[email protected]");
                att2.RSVP = false;
                att2.CommonName = "Me Jones";
                evt2.Attendees.Add(att2);



                iCalendarSerializer serializer1 = new iCalendarSerializer();

                string t = serializer1.SerializeToString(iCal1);
                Byte[] bytes = System.Text.Encoding.ASCII.GetBytes(t);

                using (var ms = new System.IO.MemoryStream(bytes))
                {
                    using (var a = new System.Net.Mail.Attachment(ms, "meeting.ics", "text/calendar")) //Either load from disk or use a MemoryStream bound to the bytes of a String
                    {
                        a.ContentDisposition.Inline = true;             //Mark as inline
                        msg.Attachments.Add(a);                          //Add it to the message
                        Mailer.Send(msg);

                    }

                }

Answer 1

Unfortunately, you're completely dependent on the implementation of Icalendar in the various email clients, and these are generally very protective of their users' calendars. They generally all support multi-event Icalendars, but invitations that "go straight in" to a users calendar have to be sent one event at a time. I'm not aware of any exceptions to this.

To process an Icalendar attachment containing more than one event, in Outlook for example, you need to save the attachment to disk, navigate to it and open it. It then opens as a separate calendar, and you need to drag the events one by one into your calendar. Nightmare. This will rarely be worth the trouble to develop.

Another option of course is to host the Icalendar on your website and get your users to subscribe by entering the calendar URL in their client. This has the advantage that changes propagate automatically, but email clients will still treat the events as external (no automatic reminders, in outlook the default is to display them in a separate pane, Gmail at least displays events from different calendars on the same grid.)