How can I Lock(set password) to a folder using c#.
Please help me
Thanks in advance

do you want to protect the data with the password for the same user or for different users ?

because there it's a difference :

For different users the windows keeps it's own User Access Control and can encrypt and decrypt files if the user has the right set of rules.

If you want to encrypt a folder by password for the same user and/or other users in the same time, then you need to find a formula so that the folder name is visible but protected.