C# how to create a hyperlink to a .ICS file in a email

Question

I have created a calender.ics file attachment to an email being sent to a user. The user then can add the appointment details to their calendar(whichever they choose Outlook, Google calendar, Yahoo! ect.). The .ics file works beautifully if I click on the attachment and download the file, but I've endlessly searched for a decent example where there is a "Add to Calendar" hyperlink or how to go about it with no real success. Is there way to accomplish this in C#? Am I missing something? This is my first stab at Icalender and I'm using StringBuilder() to build out the .ICS file.

        var customerMailMessage = new MailMessage(Store.LocationEmail, CustomerEmail);
        customerMailMessage.Subject = "Appointment Request For " + ServiceDate.ToShortDateString();
        customerMailMessage.Body = body.ToString();
        customerMailMessage.IsBodyHtml = true;

        //Start of calender invite
        DateTime ServiceTime = ServiceDate.Date.Add(StartTime.TimeOfDay);
        DateTime DateStart = Convert.ToDateTime(ServiceTime);
        string DateFormat = "yyyyMMddTHHmmssZ";
        string now = DateTime.Now.ToUniversalTime().ToString(DateFormat);
        string Location = string.Format(Store.LocationAddress1 + " " + Store.LocationCity + " " + Store.LocationState + " " + Store.LocationZip);
        string Summary = "Calendar reminder";
        string Description = "Your appointment details on: " + DateStart;
        string FileName = "ServiceAppointment.ics";
        Guid guid = Guid.NewGuid();

        StringBuilder sb = new StringBuilder();
        sb.AppendLine("BEGIN:VCALENDAR");
        sb.AppendLine("VERSION:2.0");
        sb.AppendLine("PRODID:Domain.com");
        sb.AppendLine("CALSCALE:GREGORIAN");
        sb.AppendLine("METHOD:REQUEST");
        sb.AppendLine("BEGIN:VEVENT");
        sb.AppendLine("UID:" + guid);
        sb.AppendLine(string.Format("ORGANIZER:MAILTO:{0}", retailStore.LocationEmail));
        sb.AppendLine(string.Format("ATTENDEE;CN='{0}, {1}';ROLE=REQ-PARTICIPANT;PARTSTAT=TENTATIVE:MAILTO:{2}", CustomerFirstName, CustomerLastName, CustomerEmail));
        sb.AppendLine("DTSTART:" + DateStart.ToUniversalTime().ToString(DateFormat));
        sb.AppendLine("DTSTAMP:" + now);
        sb.AppendLine("SUMMARY: " + Summary);
        sb.AppendLine("LOCATION: " + Location);
        sb.AppendLine("DESCRIPTION:" + Description);
        sb.AppendLine("PRIORITY:5");
        sb.AppendLine("TRANSP:OPAQUE");
        sb.AppendLine("END:VEVENT");
        sb.AppendLine("END:VCALENDAR");

        var calendarBytes = Encoding.UTF8.GetBytes(sb.ToString());
        System.IO.MemoryStream stream = new System.IO.MemoryStream(calendarBytes);
        Attachment attachment = new Attachment(stream, FileName, "text/calendar");
        customerMailMessage.Attachments.Add(attachment);

        System.Net.Mime.ContentType contype = new System.Net.Mime.ContentType("text/calendar");
        contype.Parameters.Add("method", "REQUEST");
        contype.Parameters.Add("name", "ServiceAppointment.ics");


        var emailProvider = new EmailProvider();
        emailProvider.Send(customerMailMessage, "Request Appointment - Customer - " + CreatedBySource);

Answer 1

Short-answer: A link in the body of the message would not invoke the method[s] on the server-side to convert the ICS file into a Calendar Item for the user's mailbox; especially, considering each platform mentioned (Exchange, Google Mail, Yahoo Mail, etc.) has it's own implementation for doing so (whether via web or client).

As an example, you can read Microsoft's Open Specification for converting an iCal to an Appointment item here.