Here's my scenario.
I have a list on SharePoint 2010, which contains thousands of items of user information. I need to update all items according to a spreadsheet on a daily basis. So, apparently I have to call SPWeb.EnsureUser() to get SPUser object from a login name (Does anybody know another way to do so?). But my network access to AD server is very slow (takes about 10 sec to validate one user), and the worse thing is a system exception (my code catches all exceptions) will be thrown out after about 100 user validations. I guess it might be some kind of security mechanism of AD server.
So, I configure the User Profile Synchronization service and successfully sync all user entries to local server. The question is, I don't know how to make the Person Picker control or the EnsureUser() function validate based on UPS, neither can I get a SPUser object from local user profiles.
I run Get-SPUser from mgmt shell and find only users that have been added into the People and Groups or validated in Person Picker control are listed. It's really annoying. I'm not supposed to add all users in AD into SP groups manually, ain't I?
Can somebody tell me what I should do and what the heck the UPS are designed for?
Thank you!