问题
How can I mark and reset the inpustream of attachments file from SMTP server for multiple reuse later?Any suggestions will be welcome.
回答1:
you are not willing to create the service now, I think you are stuck with the scenario you describe. There are some things though you could do to circumvent the problem of no user firing up the client anymore while there are still pending messages.
You could add a commandline utility that will only check for pending messages and try to send them.
Add this commandline utility to the StartUp folder or Run key in the registry. This way messages will at least get sent when the computer restarts, even if the user does not fire up the your app.
Add a scheduled task to run this utility at least once every day. The scheduled task can be added by code or by your installer.
If you do both, you will only have to worry about pending messages of users that never start their computer again.
来源：https://stackoverflow.com/questions/40990095/how-to-mark-reset-attachments-from-smtp-server