Create iCal ics Files in C# ASP.NET Core

CalendarNotificationModel.cs

public class CalendarNotificationModel
    {
        public string Name { get; set; }
        public IEnumerable<Attendee> Attendees { get; set; }
        public DateTime StartDateTime { get; set; }
        public string CreatorEmail { get; set; }
        public string Location { get; set; }
        public string Description { get; set; }
    }

    public class Attendee
    {
        public string AttendeeName { get; set; }
        public string AttendeeEmail { get; set; }
    }

CreateCalendarEvent.cs

public async Task<SendResponse> CreateCalendarEventAsync(
            CalendarNotificationModel calendarNotificationModel)
        {
            var attendees = calendarNotificationModel.Attendees.Select(x => new Ical.Net.DataTypes.Attendee()
            {
                CommonName = x.AttendeeName,
                ParticipationStatus = "REQ-PARTICIPANT",
                Rsvp = true,
                Value = new Uri($"mailto:{x.AttendeeEmail}")
            }).ToList();

            var e = new CalendarEvent
            {
                Summary = calendarNotificationModel.Name,
                IsAllDay = true,
                Organizer = new Organizer()
                {
                    CommonName = "Your app name",
                    Value = new Uri($"mailto:{[email protected]}")
                },
                Attendees = attendees,
                Start = new CalDateTime(calendarNotificationModel.StartDateTime.Date),
                Transparency = TransparencyType.Transparent,
                Location = calendarNotificationModel.Location,
                Description = calendarNotificationModel.Description
            };

            var calendar = new Calendar();
            calendar.Events.Add(e);

            var serializer = new CalendarSerializer();
            var serializedCalendar = serializer.SerializeToString(calendar);

            var bytesCalendar = Encoding.ASCII.GetBytes(serializedCalendar);
            MemoryStream ms = new MemoryStream(bytesCalendar);
            using (ms)
            {
                ms.Position = 0;

                var fileName = calendarNotificationModel.Name.Replace(' ', '_');

                var result = await _emailProviderService.SendAsync(_sendGridOptions.EmailFrom,
                    calendarNotificationModel.CreatorEmail,
                    null,
                    null,
                    "Calendar event", //Subject,
                    "Your future event details.", //Template
                    new List<Attachment>
                    {
                            new Attachment()
                            {
                                Filename = $"{fileName}.ics",
                                Data = ms,
                                ContentType = "text/calendar",
                                IsInline = false
                            }
                    },
                    true);

                return result;
            }
        }

EmailProviderService.cs

 public class EmailProviderService : IEmailProviderService
    {
        private readonly SendGridOptions _sendGridOptions;

        public EmailProviderService(IOptions<SendGridOptions> sendGridOptions)
        {
            _sendGridOptions = sendGridOptions.Value;
            FluentEmail.Core.Email.DefaultSender = new SendGridSender(_sendGridOptions.ApiKey);
            FluentEmail.Core.Email.DefaultRenderer = new RazorRenderer();
        }
        
         public async Task<SendResponse> SendAsync(string from, string to, IList<string> cc, string subject,
            string template, bool isHtml = false)
        {
            return await SendAsync(from, to, cc, null, subject, template, isHtml);
        }
        
        public async Task<SendResponse> SendAsync(string from, string to, IList<string> cc, IList<string> bcc,
            string subject, string template, IEnumerable<Attachment> attachments, bool isHtml = false)
        {
            var sendEmail = FluentEmail.Core.Email.From(from)
                .To(to)
                .Subject(subject)
                .Body(template, isHtml);

            if (cc != null)
            {
                var ccList = cc.Select(x => new Address {EmailAddress = x}).ToList();
                sendEmail = sendEmail.CC(ccList);
            }

            if (bcc != null)
            {
                var bccList = bcc.Select(x => new Address {EmailAddress = x}).ToList();
                sendEmail = sendEmail.BCC(bccList);
            }

            if (attachments != null)
            {
                sendEmail.Attach(attachments.ToList());
            }

            return await sendEmail.SendAsync();
        }
        

IEmailProviderService.cs

public interface IEmailProviderService
    {  
    Task<SendResponse> SendAsync(string from, string to, IList<string> cc, IList<string> bcc,
            string subject, string template, IEnumerable<Attachment> attachments, bool isHtml = false);
            }

SendGridOptions.cs

    public class SendGridOptions
    {
        public string ApiKey { get; set; }
        public string EmailFrom { get; set; }
    }

How to create an email with iCal file?
See this post

Hi I need a some help in this solution.
I implemented the same but having some issues in to running ,like namespace and all are not getting properly so may I have full solution ?(working/running)?

Hi,
Have you ever read this post?
What is the issue?