public bool RemoveUserToGroup(string userlogin, string groupName)
 {
     try
     {
         using (HostingEnvironment.Impersonate())
         {
             _directoryEntry = null;
             ADManager admanager = new ADManager("xxx");    // LDAPUser, LDAPPassword);
             admanager.RemoveUserFromGroup(userlogin, groupName);
             return(true);
         }
     }
     catch (Exception ex)
     {
         return(false);
     }
 }