How do you create a PDF after submitting a form and attach it to an automated email in ASP.NET MVC C#?

Question

I am having the hardest time figuring out how to create a pdf and attach it to an automated email. I thought it wouldn't be that hard but have quickly found out that it is much more complex than I imagined. Anyways, what I am doing is I have an order form, and when the customer fills out an order and submits it, I want it to generate a PDF for that order and attach it to an automated confirmation email. I am currently using Rotativa to generate the pdf and if I just ran the action result for generating it, it works perfectly fine which looks something like this:

public ActionResult ProcessOrder(int? id)
{
   string orderNum = "FulfillmentOrder" + orderDetail.OrderID + ".pdf";
   var pdf = new ActionAsPdf("OrderReportPDF", new { id = orderDetail.OrderID }) { FileName = orderNum };
   return pdf;
}

When I added the function to send an automated email after the order form was submitted, that works perfectly fine with just the email by itself. But I can't seem to figure out how to generate the pdf and attach it to the email. The report view that gets the data from the order form is called "OrderReportPDF". My order form is called "Checkout", but the action result I use for this is called "Process Order". I've taken out the code in this function that is for the order form as it is not applicable. The section of my code for sending the email after the form is submitted is:

public ActionResult ProcessOrder(int? id)
{
   //Send a confirmation email
   var msgTitle = "Order Confirmation #" + orderDetail.OrderID;
   var recipient = JohnDoe;
   var fileAttach = //This is where I can't figure out how to attach//
   var fileList = new string[] { fileAttach };
   var errorMessage = "";
   var OrderConfirmation = "Your order has been placed and is pending review." +
                           " Attached is a copy of your order.";
            
  try
  {
    // Initialize WebMail helper
    WebMail.SmtpServer = "abc.net";
    WebMail.SmtpPort = 555;
    WebMail.UserName = recipient;
    WebMail.Password = "12345";
    WebMail.From = "orders@samplecode.com";

    // Send email
    WebMail.Send(to: "orders@samplecode.com",
    subject: msgTitle,
    body: OrderConfirmation,
    filesToAttach: fileList
    );
  }
  catch (Exception ex)
  {
    errorMessage = ex.Message;
  }
  //5. Remove item cart session
       Session.Remove(strCart);
       return View("OrderSuccess");
}

I have been able to find very few articles on this issue using Rotativa and the ones I have found don't work for what I'm doing. Maybe Rotativa won't work for this, I'm hoping it does because I've designed my pdf report it generates from it, and not sure if doing it another way will screw up my formatting of it or not. As you can see at the bottom of the code, I return the view to an "OrderSuccess" page. When I try to implement the first code into the second code, it won't let me "return pdf" to execute the ActionAsPdf that generates the pdf when I do the "return View("OrderSuccess")". It only lets me do one or the other. If anybody knows how I can accomplish this, I need some help. I appreciate any suggestions or feedback. I'm pretty new to this so please be patient with me if I don't understand something.

Answer 1

Here is the updated code that fixed my problem and created the pdf, then attached it to an automated email once the order form was submitted:

 public ActionResult ProcessOrder(int? id)
 {
    //1. Generate pdf file of order placed
    string orderNum = "FulfillmentOrder" + orderDetail.OrderID + ".pdf";
    var actionResult = new Rotativa.ActionAsPdf("OrderReportPDF", new { id = orderDetail.OrderID }) { FileName = orderNum };
    var PdfAsBytes = actionResult.BuildFile(this.ControllerContext);

    //2. Send confirmation email
    var msgTitle = "Order Confirmation #" + orderDetail.OrderID;
    var OrderConfirmation = "Your order has been placed and is pending review.<br />" +
                            " Attached is a copy of your order." +

    using (MailMessage mail = new MailMessage())
    {
       mail.From = new MailAddress("orders@samplecode.com");
       mail.To.Add("orders@samplecode.com");
       mail.Subject = msgTitle;
       mail.Body = OrderConfirmation;
       mail.IsBodyHtml = true;
       //STREAM THE CONVERTED BYTES AS ATTACHMENT HERE
       mail.Attachments.Add(new Attachment(new MemoryStream(PdfAsBytes), orderNum));

       using (SmtpClient smtp = new SmtpClient("abc.net", 555))
       {
           smtp.Credentials = new NetworkCredential("orders@samplecode.com", "password!");
           smtp.EnableSsl = true;
           smtp.Send(mail);
       }
     }
     //3. Remove item cart session
     Session.Remove(strCart);
     return View("OrderSuccess");
  }

Thank you again to the people that helped and got me pointed in the right direction! Also, a quick shout out to @Drewskis who posted this answer in convert Rotativa.ViewAsPdf to System.Mail.Attachment where I was able to use it to solve my issue!