Redmine

Can this be achieved by limiting registration to LDAP...?

For example, you company have 300+person, only register use can create a issue, create 300+ user need a lot of time, so you let user register themselfs, but you do not want other person register, cause redmine is open for Internet

I see what you're saying. I'm wondering if you could disable self-registration entirely, configure LDAP access in Redmine settings to your work network, and have users created on-the-fly the first time they attempt to sign into Redmine.

LDAP would basically let Redmine authenticate users with their standard work/email credentials. If they don't exist on your mail server, they can't proceed.

The last LDAP configuration I looked at used a plugin to sync the Exchange server's address book to Redmine's user list, automatically creating user accounts for everyone, which is different from the on-demand creation I described above. I don't know enough about LDAP+Redmine to give you step-by-step instructions, but I do believe what you want to do is possible somehow through this path. Odds are very good that whatever your company is using for email offers LDAP access.

yes,I can solve this problem directly by modify code,however,if there have this function is a good thing

I'm wondering if you could disable self-registration entirely, configure LDAP access in Redmine settings to your work network, and have users created on-the-fly the first time they attempt to sign into Redmine.

This is possible without using any plugins -- it's what the Redmine instance I use does