title: Send email to Outlook with ics meeting appointment
body: <p>I want to send an email with appointment\meeting (ICS) to Outlook client. When the user receive the email he should accept the meeting invitation and automatically the meeting goes to the calendar and the email is automatically deleted.</p>
  
  <p>I'm using this code:</p>
  
  <pre><code>public void Sendmail_With_IcsAttachment()
  {
  
      MailMessage msg = new MailMessage();
      //Now we have to set the value to Mail message properties
  
      //Note Please change it to correct mail-id to use this in your application
      msg.From = new MailAddress("xxxxx@xyz.com", "ABC");
      msg.To.Add(new MailAddress("yyyyy@xyz.com", "BCD"));
      msg.CC.Add(new MailAddress("zzzzz@xyz.com", "DEF"));// it is optional, only if required
      msg.Subject = "Send mail with ICS file as an Attachment";
      msg.Body = "Please Attend the meeting with this schedule";
  
      // Now Contruct the ICS file using string builder
      StringBuilder str = new StringBuilder();
      str.AppendLine("BEGIN:VCALENDAR");
      str.AppendLine("PRODID:-//Schedule a Meeting");
      str.AppendLine("VERSION:2.0");
      str.AppendLine("METHOD:REQUEST");
      str.AppendLine("BEGIN:VEVENT");
      str.AppendLine(string.Format("DTSTART:{0:yyyyMMddTHHmmssZ}", DateTime.Now.AddMinutes(+330)));
      str.AppendLine(string.Format("DTSTAMP:{0:yyyyMMddTHHmmssZ}", DateTime.UtcNow));
      str.AppendLine(string.Format("DTEND:{0:yyyyMMddTHHmmssZ}", DateTime.Now.AddMinutes(+660)));
      str.AppendLine("LOCATION: " + this.Location);
      str.AppendLine(string.Format("UID:{0}", Guid.NewGuid()));
      str.AppendLine(string.Format("DESCRIPTION:{0}", msg.Body));
      str.AppendLine(string.Format("X-ALT-DESC;FMTTYPE=text/html:{0}", msg.Body));
      str.AppendLine(string.Format("SUMMARY:{0}", msg.Subject));
      str.AppendLine(string.Format("ORGANIZER:MAILTO:{0}", msg.From.Address));
  
      str.AppendLine(string.Format("ATTENDEE;CN=\"{0}\";RSVP=TRUE:mailto:{1}", msg.To[0].DisplayName, msg.To[0].Address));
  
      str.AppendLine("BEGIN:VALARM");
      str.AppendLine("TRIGGER:-PT15M");
      str.AppendLine("ACTION:DISPLAY");
      str.AppendLine("DESCRIPTION:Reminder");
      str.AppendLine("END:VALARM");
      str.AppendLine("END:VEVENT");
      str.AppendLine("END:VCALENDAR");
  
      //Now sending a mail with attachment ICS file.                     
      System.Net.Mail.SmtpClient smtpclient = new System.Net.Mail.SmtpClient();
      smtpclient.Host = "localhost"; //-------this has to given the Mailserver IP
  
      smtpclient.Credentials = System.Net.CredentialCache.DefaultNetworkCredentials;
  
      System.Net.Mime.ContentType contype = new System.Net.Mime.ContentType("text/calendar");
      contype.Parameters.Add("method", "REQUEST"); 
      contype.Parameters.Add("name", "Meeting.ics");
      AlternateView avCal = AlternateView.CreateAlternateViewFromString(str.ToString(), contype);
      msg.AlternateViews.Add(avCal);
      smtpclient.Send(msg); 
  }
  </code></pre>
  
  <p>The mail is correctly sent but in outlook (I'm testing it with outlook 2010) it shows the body, location,data, and it shows the calendar but above the calendar in the mail I see "Impossible to find the meeting on the calendar" and the "Accept","Decline"" buttons are disabled!</p>
  
  <p>I have tried other solutions and found on the web for ex. DDAY.Ical but I haven't found any example to use it.</p>