Send email with Attachments and Calendar Invite

Question

I am working on service where I want to send emails with attachments(image, pdf, docs) and ics calendar invitation as an alternateview. Whenever I am sending mail with attachments the ics calendar invitation is missing in a mail but when I don't have any attachments in mail then I am able to receive calendar invitation.

Here is my code

if (Convert.ToString(DR["ATTACHMENT"]) != "")   //mail_att
{
    message.Attachments.Add(new Attachment(DR["ATTACHMENT"].ToString()));
}
if (Convert.ToString(DR["SCRIPT"]) != "")   //Mail_Sub
{
    System.Net.Mime.ContentType ct = new System.Net.Mime.ContentType("text/calendar");
    ct.Parameters.Add("method", "REQUEST");
    ct.Parameters.Add("name", "meeting.ics");
    AlternateView avCal = AlternateView.CreateAlternateViewFromString(Convert.ToString(DR["SCRIPT"]), ct);
    message.AlternateViews.Add(avCal);
}

MailMessage object message is showing Attachments and AlternateView counts, still calendar invite is missing in mails whenever I add attachments.

score 0 · Answer 1 · answered Jul 29 '20 at 11:40

Take a look on topic Send email to Outlook with ics meeting appointment

// 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");

You can see this in code `Convert.ToString(DR["SCRIPT"])` I am passing the script. — Shreyas Pednekar, Jul 29 '20 at 11:45
ics invite is working fine without attachments but whenever I add attachments, meeting invite is missing in a mail — Shreyas Pednekar, Jul 29 '20 at 11:46

score 0 · Accepted Answer · answered Aug 03 '20 at 04:42

If you are sending using straight SMTP, the attachments must be embedded inside the VEVENT part in an ATTACH field:

ATTACH;ENCODING=BASE64;VALUE=BINARY;X-FILENAME=test.txt:NBIBANyGrhFvX6xL...

Create an appointment with an attachment in Outlook and save it as an ICS file from Outlook as a test then open that ICS file in notepad then you can check how the script looks like, makes changes in your AlternateView calendar script

Send email with Attachments and Calendar Invite

2 Answers2