4

我目前正在调试一个问题，但在MSDN 文档中找不到这个问题的答案

我有以下代码：

if(attachmentFileName != null && File.Exists(attachmentFileName))
{
    mail.Attachments.Add(new Attachment(attachmentFileName, MediaTypeNames.Application.Octet));
}

using(SmtpClient smtp = new SmtpClient { UseDefaultCredentials = true })
{
    try
    {
        smtp.Send(mail);
    }
    catch(SmtpException ex)
    {
        if(attachmentFileName != null && ex.StatusCode == SmtpStatusCode.ExceededStorageAllocation)
        {
            //Need to still send the mail. Just strip out the attachment & add footer saying that attachment has been stripped out.
            mail.Attachments.Clear();
            mail.Body += "\n\nNote: Please note that due to outbound size limitations, attachments to this email have been stripped out.\n";
            smtp.Send(mail);
        }
        else
        {
            throw;
        }
    }
}

在更高级别（此方法的调用者），我有以下内容：

try
{
    SendEmail(recipients, alertTitle, body, alertID, subjectPrefix, merchantIDValue, attachmentFilePath);
}
finally
{
    if(tempFile != null)
    {
        File.Delete(tempFile);
    }
}

我将代码部署到我们的测试环境中，现在我的错误日志中出现以下异常：

System.IO.IOException: The process cannot access the file 'C:\fileName.zip' because it is being used by another process.
   at System.IO.__Error.WinIOError(Int32 errorCode, String maybeFullPath)
   at System.IO.File.Delete(String path)
   at AlertDelivery.CreateAttachmentFile(String attachmentData, String merchantID, String reportTitle) in d:\svn\trunk\Solution\Alerting\AlertDelivery.cs:line 143
   at AlertDelivery.TrySendAlert(String merchantID, String reportTitle, Int32 alertID, String alertTitle, String attachmentData, String attachmentFilePath, String body, Boolean isReport, String subjectPrefix, List`1 recipients) in d:\svn\trunk\Solution\Alerting\AlertDelivery.cs:line 110
   at AlertingService.ProcessAlertEvents(Object parameters) in d:\svn\trunk\Solution\Alerting\AlertingService.cs:line 174

第 174File.Delete(tempFile);行是调用者代码中的行。

SmtpClient.SendSmtpClient 是否在调用后对附件保持异步锁定？还有什么明显的问题吗？

4

2 回答 2

10

尝试mail使用 using 语句封装
您的变量

public void SendEmail(...)
{
    using(MailMessage mail = new MailMessage())
    {

      .... your code above
    }

}

这将强制对 MailMessage 对象进行 dispose 调用，并且该调用还会释放任何附件。

于 2013-01-25T22:26:59.930 回答
7

确实如此，直到您处理掉 MailMessage 对象。

于 2013-01-25T22:24:49.130 回答