Create Outlook VCalendar reminder file and attach it into an email using C#.net

Using the below code example you can create Outlook calendar file with extention .ics. Then, using System.Net.Mail you can attach it into an email as binary data.

// CreateAppointment creates email attachment containing outlook calendar file.
// Attachment representing a calendar appointment

string AppointmentFileName = "Your file name";
string AppointmentSummary = "Your appointment summary";
string AppointmentDescription = "Your appointment description";
int AppointmentDuration = 20;            // Choose appropriate time duration
private System.Net.Mail.Attachment CreateAppointment()
{

// Building .ics file string

string filestring = "BEGIN:VCALENDAR" + Environment.NewLine +
                         "VERSION:1.0" + Environment.NewLine +
                         "BEGIN:VEVENT" + Environment.NewLine +
                         "DTSTART:" + DateTime.Parse(TextBoxDate.Text).ToString("s") + Environment.NewLine +
                         "DTEND:" + DateTime.Parse(TextBoxDate.Text).AddMinutes                                            (AppointmentDuration).ToString("s")
                         +  Environment.NewLine +
                         "SUMMARY:" + AppointmentSummary + Environment.NewLine +
                         "DESCRIPTION:" + AppointmentDescription + Environment.NewLine +
                         "END:VEVENT" + Environment.NewLine +
                         "END:VCALENDAR";

// Convert filestring into binary.

byte[] filedata = Encoding.UTF8.GetBytes(filestring);
MemoryStream memorystream = new MemoryStream(filedata);


System.Net.Mail.Attachment appointment = new System.Net.Mail.Attachment(memorystream, AppointmentFilename, "text/calendar");


return appointment;
}