Assembly: mscorlib (in mscorlib.dll)
The method applies access control list (ACL) entries to a file that represents the noninherited ACL list.
The ACL specified for the fileSecurity parameter replaces the existing ACL for the file. To add permissions for a new user, use the GetAccessControl method to obtain the existing ACL, modify it, and then use to apply it back to the file.
An ACL describes individuals and/or groups who have, or do not have, rights to specific actions on the given file. For more information, see How to: Add or Remove Access Control List Entries.