该进程无法访问文件名，因为它正在被另一个进程使用

Question

I am generating PDFs with this Code:

foreach (var emp in empList)
{
    ....    
    Byte[] bytes;
    using (var ms = new MemoryStream())
    {

        //Create an iTextSharp Document which is an abstraction of a PDF but **NOT** a PDF
        using (var doc = new Document())
        {

            //Create a writer that's bound to our PDF abstraction and our stream
            using (var writer = PdfWriter.GetInstance(doc, ms))
            {
                //Open the document for writing
                doc.Open();

                using (var htmlWorker = new iTextSharp.text.html.simpleparser.HTMLWorker(doc))
                {

                    //HTMLWorker doesn't read a string directly but instead needs a TextReader (which StringReader subclasses)
                    using (var sr = new StringReader(EmailBody))
                    {

                        //Parse the HTML
                        htmlWorker.Parse(sr);
                    }
                }

                doc.Close();
            }
        }

        bytes = ms.ToArray();
    }

    bool isexist = System.IO.Directory.Exists(Server.MapPath("~/" + Session["SchemaName"].ToString() + "/HRLetters"));
    if (!isexist)
    {
        System.IO.Directory.CreateDirectory(Server.MapPath("~/" + Session["SchemaName"].ToString() + "/HRLetters"));
    }
    System.IO.File.WriteAllBytes(Server.MapPath("~/" + Session["SchemaName"].ToString() + "/HRLetters/" + emp.Code.ToString() + ".pdf"), bytes.ToArray());
}

Then I send all the PDF files as an attachment through mail with this Code:

.......
SmtpClient smtp = new SmtpClient
                {
                    Host = data.SMTPServer, // smtp server address here...                    
                    Port = data.PortNo,
                    EnableSsl = data.SSL,
                    DeliveryMethod = SmtpDeliveryMethod.Network,
                    Credentials = new System.Net.NetworkCredential(senderID, senderPassword),
                    Timeout = 30000,
                };
                Thread th = new Thread(() => { smtp.Send(message); });
                th.Start();

Then finally I try to the delete the folder:

if (System.IO.Directory.Exists(Server.MapPath("~/" + Session["SchemaName"].ToString())))
{
    System.IO.Directory.Delete(Server.MapPath("~/" + Session["SchemaName"].ToString()), true);
}

I get the Error:

The process cannot access the file '001.pdf' because it is being used by another process.

How to solve this Issue? Is this happening because of the Thread running at the time of Mail send?

Answer 1

Some handle is still open to the pdf file while you try to delete it in the main thread. You should delete them in the sending thread .