发送电子邮件ASP.NET MVC 5后删除Rotativa pdf

Question

I am able to generate pdf using Rotativa and using the code below. So I save the pdf and email as an attachment. Now my problem is how to delete this file. The file generation and emailing could take a while so when the delete call is made it generates an error: The process cannot access the file ....blah/blah.pdf because it is being used by another process.

I need help to be able to clean up the files generated. These files span a years worth of records and take up quite a bit of space and time to generate.

How do I make the delete call take place when the file has been completely emailed and released?

public ActionResult Receipt(int year, int Id, ReceiptViewModel model)
        {
            var root = Server.MapPath("~/App_Data/");
            var pdfname = String.Format("{0}-{1}-{2}.pdf", Id, year, Guid.NewGuid().ToString());
            var path = Path.Combine(root, pdfname);
            path = Path.GetFullPath(path);
            IUserMailer mailer = new UserMailer();


            var a = new ViewAsPdf("Receipt", new { Id, year })
            {
                FileName = pdfname,
                PageSize = Rotativa.Options.Size.A5,
                PageOrientation = Rotativa.Options.Orientation.Portrait,
                SaveOnServerPath = path
            };

            var byteArray = a.BuildFile(ControllerContext);
            var fileStream = new FileStream(path, FileMode.Create, FileAccess.Write);
            fileStream.Write(byteArray, 0, byteArray.Length);
            fileStream.Close();
       // email the pdf as attachment  
      mailer.BulkReceipt(path, pdfname, Id, year).SendAsync();
      // Delete file
System.IO.File.Delete(path);
            return View("ReceiptSuccess", a);


        }

Answer 1

You could..., make an in mem copy of the file and then tell the mailer to use that version(in mem).... which means you can delete the local physical file. the in mem version will clean itself up once no-longer used.

Answer 2

Usually a method with Async in its name will call a callback method when it is complete or return a Task.

Often the callback will be passed into the method, something like below:

mailer.BulkReceipt(path, pdfname, Id, year).SendAsync(() => System.IO.File.Delete(path));

But sometimes there is a separate event that you need to wire up on your object with the callback for the when it is finished. In this case it could be called SendComplete or something similar.

If the SendAsync call returns a Task, then you probably want to call await and make your Receipt method async:

public async Task<ActionResult> Receipt(int year, int Id, ReceiptViewModel model)
{
    ...
    await mailer.BulkReceipt(path, pdfname, Id, year).SendAsync();
    // Delete file
    System.IO.File.Delete(path);

    return View("ReceiptSuccess", a);
}

Or something similar to that...