protected void OnUserDeleteClicked(object sender, EventArgs e)
    {
        LinkButton lnkItem = (LinkButton)sender;
        string userID = lnkItem.CommandArgument;

        //Check whether this user is being used
        //Delete user's permissions first.
        ParamUserPermissionRepository perRepo = new ParamUserPermissionRepository();
        IList<ParamUserPermission> oldPerList = perRepo.GetPermissionsOfUser(userID);
        foreach (ParamUserPermission deletePer in oldPerList)
        {
            perRepo.DeleteUserPermission(deletePer);
        }

        //Delete user
        ParamUser deleteItem = new ParamUser(userID);
        ParamUserRepository repo = new ParamUserRepository();
        repo.Delete(deleteItem);

        BindGridData();
        gridUsers.DataBind();
    }