title: Emails with event invite generated by MVC application not synced with calendar in outlook.com
body: <p>I am creating ASP.NET MVC5 application. One functionality is to send emails with event invitations. In Gmail client such generated email works fine. But in outlook.com even if the email has correct buttons - accept/tentative/decline - clicking on them won't sync that into the calendar itself.</p>
  
  <p>I took some inspiration here:</p>
  
  <p><a href="https://stackoverflow.com/questions/10426661/sending-outlook-meeting-requests-without-accept-decline-option">StackOverflow Q1</a><br/>
  <a href="https://stackoverflow.com/questions/32375783/ics-invitation-calendar-not-working-in-outlook-com-issue">StackOverflow Q2</a><br/>
  <a href="https://stackoverflow.com/questions/19523861/multipart-email-with-text-and-calendar-outlook-doesnt-recognize-ics/19535685#19535685">StackOverflow Q3</a><br/></p>
  
  <p>Here is my current implementation:</p>
  
  <p>I am using DDay.ical library for creating the event:</p>
  
  <pre><code>IICalendar iCal = new iCalendar();
  iCal.Version = "2.0";
  iCal.Method = "REQUEST";
  iCal.ProductID = "my@product.com";
  
  Event evt = iCal.Create&lt;Event&gt;();
  evt.UID = Guid.NewGuid().ToString();
  evt.Class = "PUBLIC";
  evt.Created = new iCalDateTime(DateTime.Now);
  evt.DTStamp = new iCalDateTime(DateTime.Now);
  evt.Start = new iCalDateTime(DateTime.Now.AddHours(2));
  evt.End = new iCalDateTime(DateTime.Now.AddHours(4));
  evt.Location = "Party room";
  evt.Description = "Awesome party";
  evt.Summary = "Lets get wasted";
  evt.Priority = 5;
  evt.Transparency = TransparencyType.Transparent;
  
  string res = new iCalendarSerializer().SerializeToString(iCal);
  return res;
  </code></pre>
  
  <p>I am packing this event into email as an alternative view:</p>
  
  <pre><code>MailMessage email = new MailMessage();
  
  email.To.Add(addressesToJoined);
  email.Subject = Party;
  email.Body = "";
  
  if (!String.IsNullOrEmpty(calendarEvent))
  {
      System.Net.Mime.ContentType calendarType = new System.Net.Mime.ContentType("text/calendar");
      calendarType.Parameters.Add("method", "REQUEST");
  
      AlternateView ICSview = AlternateView.CreateAlternateViewFromString(calendarEvent, calendarType);
  
      email.AlternateViews.Add(ICSview);
  
  }
  </code></pre>
  
  <p>And here is the .ics itself:</p>
  
  <pre><code>BEGIN:VCALENDAR
  VERSION:2.0
  METHOD:REQUEST
  PRODID:my@product.com
  BEGIN:VEVENT
  CLASS:PUBLIC
  CREATED:20151115T152442
  DESCRIPTION:Awesome party
  DTEND:20151115T192442
  DTSTAMP:20151115T142442Z
  DTSTART:20151115T172442
  LOCATION:Party room
  PRIORITY:5
  SEQUENCE:0
  SUMMARY:Lets get wasted
  TRANSP:Transparent
  UID:1735cdca-cb36-4e6b-a1ec-4fb4149f798a
  END:VEVENT
  END:VCALENDAR
  </code></pre>
  
  <p>When this email comes to Gmail client, I can correctly see the invitation with option to add event into calendar, which works fine.</p>
  
  <p>But in outlook.com even when the email itself is correctly recognized as invitation and I can see accept/tentative/decline buttons it does not work as expected. When I click for example accept option, new response email is created and when I send it out, I would expect, the event will be set in my calendar, however there is no event synced.</p>
  
  <p>Can someone please see why events are not synced in calendar in outlook.com?
  Also, is there possibility in outlook.com to just set event in calendar, without sending response email? - invitations are auto-generated from system no need for response.</p>
  
  <p>Thanks</p>