Send meeting request in SharePoint custom workflow

Working with SharePoint workflow I got a requirement to send meeting request by using the code. I have dig into deep to check if there is any option to send meeting requests by using SharePoint workflow but I couldn’t find anything. So we have only option to send meeting request through C# code.

My friend Ravi helped me on the code finally by using the code below we are able to send the meeting requests.

private void SendMeetingRequestMail(VacationRequestMail reqMail, string smtpTO, string smtpServer, string smtpFrom)

        {

            using (MailMessage mailMessage = new MailMessage(smtpFrom, smtpTO))

            {

                mailMessage.Subject = “Subject”;

                mailMessage.Body = “Body”;

                DateTime startDate = “Start Date and Time”

                DateTime endDate = “End Date and Time”

                StringBuilder str = new StringBuilder();

                str.AppendLine("BEGIN:VCALENDAR");

                str.AppendLine("PRODID:-//Vacation Request Portal");

                str.AppendLine("VERSION:2.0");

                str.AppendLine("METHOD:REQUEST");

                str.AppendLine("BEGIN:VEVENT");

                str.AppendLine(string.Format("DTSTART:{0:yyyyMMddTHHmmssZ}", startDate));

                str.AppendLine(string.Format("DTEND:{0:yyyyMMddTHHmmssZ}", endDate));

                str.AppendLine("LOCATION: Vacation Request Portal, India");

                str.AppendLine(string.Format("X-MICROSOFT-CDO-ALLDAYEVENT:TRUE"));

                str.AppendLine(string.Format("UID:{0}", Guid.NewGuid()));

                str.AppendLine(string.Format("DESCRIPTION:{0}", mailMessage.Body));

                str.AppendLine(string.Format("X-ALT-DESC;FMTTYPE=text/html:{0}", mailMessage.Body));

                str.AppendLine(string.Format("SUMMARY:{0}", mailMessage.Subject));

                str.AppendLine(string.Format("ORGANIZER:MAILTO:{0}", mailMessage.From.Address));

                str.AppendLine("X-MICROSOFT-CDO-BUSYSTATUS:FREE");

                str.AppendLine("BEGIN:VALARM");

                str.AppendLine("TRIGGER:-PT18H");

                str.AppendLine("ACTION:DISPLAY");

                str.AppendLine("DESCRIPTION:Reminder");

                str.AppendLine("END:VALARM");

                str.AppendLine("END:VEVENT");

                str.AppendLine("END:VCALENDAR");

                System.Net.Mime.ContentType ct = new System.Net.Mime.ContentType("text/calendar");

                ct.Parameters.Add("method", "REQUEST");

                AlternateView avCal = AlternateView.CreateAlternateViewFromString(str.ToString(), ct);

                mailMessage.AlternateViews.Add(avCal);

                using (SmtpClient smtpClient = new SmtpClient(smtpServer))

                {

                    smtpClient.Send(mailMessage);

                }

            }

        }

We have multiple options while sending meeting requests. For example “X-MICROSOFT-CDO-BUSYSTATUS:FREE” will set the user state to free even user accept the meeting request. Hope this will help.