我这样测试没问题
Dim dirPath = "d:\test"
Dim dir As New io.DirectoryInfo(dirPath)
Dim dirSecurity As System.Security.AccessControl.DirectorySecurity = dir.GetAccessControl(System.Security.AccessControl.AccessControlSections.All)
Dim [inherits] As System.Security.AccessControl.InheritanceFlags = System.Security.AccessControl.InheritanceFlags.ContainerInherit Or System.Security.AccessControl.InheritanceFlags.ObjectInherit
Dim everyoneFileSystemAccessRule As System.Security.AccessControl.FileSystemAccessRule = New System.Security.AccessControl.FileSystemAccessRule("Everyone", System.Security.AccessControl.FileSystemRights.FullControl, [inherits], System.Security.AccessControl.PropagationFlags.None, System.Security.AccessControl.AccessControlType.Allow)
Dim usersFileSystemAccessRule As System.Security.AccessControl.FileSystemAccessRule = New System.Security.AccessControl.FileSystemAccessRule("Users", System.Security.AccessControl.FileSystemRights.FullControl, [inherits], System.Security.AccessControl.PropagationFlags.None, System.Security.AccessControl.AccessControlType.Allow)
Dim isModified As Boolean = False
dirSecurity.ModifyAccessRule( System.Security.AccessControl.AccessControlModification.Add, everyoneFileSystemAccessRule, isModified)
dirSecurity.ModifyAccessRule( System.Security.AccessControl.AccessControlModification.Add, usersFileSystemAccessRule, isModified)
dir.SetAccessControl(dirSecurity)