Where to store the user Id, while using a network database

We have a C#.Net application which uses a network database. I mean to say that many instances of the application will access the same db from different machines. So if I have to store the user-id to show the user while re-logging in, where can I store it?

The options i have are:

- Storing it in a local file in application directory. (But the problem is that the application is installed using Click Once. When the application is updated the application directory is being changed. May be I am missing something here.)

- Storing in t开发者_JAVA技巧he registry.

Are there any other?

Can some one please suggest what to do? Correct me if I am wrong.

There are buil-int locations for this kind of stuff see Environment - specifically:

• ApplicationData (user-specific roaming)
• LocalApplicationData (user-specific non-roaming)
• CommonApplicationData (not user-specific)

Generally you want to store any data that needs to persist between sessions, and is user specific in the registry, or the user AppData folder. Normally for small things (i.e. ids, basic settings etc....) the registry is the best place. Just make sure to stick it under HKCU\Software\Your company name\your program name. Although if the data is sensitive you should be careful where you place it, and it should be encryptedto protect it from basic snooping. If it's data that isn't sensitive though then the registry is a good place to put it.

This assumes of course that the installation and configuration doesn't need to be xcopy portable (i.e. a user could just copy the installation folder to a new place/computer and have everything work as normal). If that's the case then you'll want to store it under the installation directory.

If you need to store the UserID on the local, keep it in some kind of configuration file, mabe under a "LastLogin" entry. Check out this question and specifically this answer for more information.

Consider using Isolated Storage