Sending an Entity on email using Mailer ASP.net

Question

Trying to develop an app where when a User applies for an appointment, they get email confirmation that the appointment has been received with their details in the email. I've got a linq query( after the appointment is created) to get their details from the database. I've debugged the app, and the details are going through to the mailer method. However, I get a blank email. Is it something to do with the ViewBag.Data?

Here's where I send the details:

 var app = (from a in db.Appointments
                where appointments.AppointmentId == a.AppointmentId
                   select a).FirstOrDefault()

                UserMailer.AppointmentDetails(app).Send();

My mailer method:

public virtual MvcMailMessage AppointmentDetails(Appointments appointment)
    {
        ViewBag.Data = appointment;
        return Populate(x =>
        {
            x.Subject = "Appointment Detail";
            x.ViewName = "AppointmentDetails";
            x.To.Add(appointment.ApplicantEmail);
        });
    }

Finally the view for the email:

    Appointment Details @ViewBag.Data:<br />
Welcome to the  App and enjoy your time!<br />

Answer 1

Fixed it, I needed to set up these in the mailer:

ViewBag.Details = appointment.DetailsOfAppointment;
        ViewBag.Date = appointment.DateOfAppointment;
        ViewBag.Room = appointment.RoomType;

Then assign them in my view