Move a file after an email is sent - smtpclient

Question

I am writing a program that looks for files in a folder, attaches the files to the MailMessage and sends an email using SmtpClient.
After the email is sent out successfully, I want to move the emailed files to a different folder.
I get this message "The process cannot access the file because it is being used by another process.". I tried Thread.Sleep() but did not work.
smtpClient.Send(mail);
foreach (var report in reports)
{
string source = Path.Combine(reportsFolder, report);
string destination = Path.Combine(sentReportsFolder, report);
File.Move(source, destination);
}

Answer 1

First, try to dispose your smtpclient class:
smtpClient.Send(mail);
smtpClient.Dispose();
http://msdn.microsoft.com/pt-br/library/system.net.mail.smtpclient.dispose.aspx
But, when creating the class, you could use an using statemant.
Like:
using (SmtpClient smtpClient = new SmtpClent()) {
//attach file
smtpClient.Send();
}
This will ensure that, after send an email, the class will releases any resources that might be locked by the class. So, you not need to call .Dispose() explicitly.
http://msdn.microsoft.com/pt-br/library/system.net.mail.smtpclient.aspx
http://msdn.microsoft.com/en-us/library/yh598w02.aspx