The process cannot access the file because it is being used by another process (Error occur after nu-CodePudding

I have some emails with attachments sending out. Every 56th mail will go error. And the detail of the error is:

System.Net.Mail.SmtpException: Failure sending mail. ---> System.IO.IOException: Unable to write data to the transport connection: An established connection was aborted by the software in your host machine. ---> System.Net.Sockets.SocketException: An established connection was aborted by the software in your host machine at System.Net.Sockets.Socket.Send(Byte[] buffer, Int32 offset, Int32 size, SocketFlags socketFlags) at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size) --- End of inner exception stack trace --- at System.Net.Sockets.NetworkStream.Write(Byte[] buffer, Int32 offset, Int32 size) at System.Net.DelegatedStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.DelegatedStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.Mime.SevenBitStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.DelegatedStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.DelegatedStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.Mime.SevenBitStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.DelegatedStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.DelegatedStream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.Base64Stream.FlushInternal() at System.Net.Base64Stream.Write(Byte[] buffer, Int32 offset, Int32 count) at System.Net.Mime.MimePart.Send(BaseWriter writer) at System.Net.Mime.MimeMultiPart.Send(BaseWriter writer) at System.Net.Mail.Message.Send(BaseWriter writer, Boolean sendEnvelope) at System.Net.Mail.MailMessage.Send(BaseWriter writer, Boolean sendEnvelope) at System.Net.Mail.SmtpClient.Send(MailMessage message) --- End of inner exception stack trace --- at System.Net.Mail.SmtpClient.Send(MailMessage message)

I have find some similar answer in google but it is not working. Can anyone help please? I am using .NET 3.5 which could not use SmtpClient.Dispose() Here is the similar question: Dispose method for smtpclient in .net 2.0

CodePudding user response：

Finally I find the answer for my question. It works prefectly for disposing the smtpclient for the previous .net.

Does system.net.mail.smptclient disconnect from the server?

Here is the code

var smtp = new SmtpClient();
smtp.ServicePoint.MaxIdleTime = 1;
smtp.ServicePoint.ConnectionLimit = 1;
smtp.Send(message);