System.Security.PermissionSet.PermitOnly C# (CSharp) Method

        public void PermitOnly() { throw new PlatformNotSupportedException(); }
        public IPermission RemovePermission(Type permClass) { return default(IPermission); }

        public void CanChangeConnectionSettingsOnClientPermission()
        {
            MySqlConnection dummyconn = new MySqlConnection();
              PermissionSet permissionsSet = new PermissionSet(PermissionState.None);
              MySqlClientPermission permission = new MySqlClientPermission(PermissionState.None);

              // Allow only server localhost, any database, only with root user
              permission.Add("server=localhost;", "database=; user id=root;", KeyRestrictionBehavior.PreventUsage);
              permissionsSet.AddPermission(permission);
              permissionsSet.PermitOnly();
              dummyconn.ConnectionString = "server=localhost; user id=test;includesecurityasserts=true;";
              dummyconn.Open();
              if (dummyconn.State == ConnectionState.Open) dummyconn.Close();
        }