public void Remove(object user)
        {
            if (user == Null.Value || user == Undefined.Value || user == null)
            {
                throw new ArgumentNullException("user", @"A user to remove must be specified either by id or login name.");
            }

            if (TypeUtilities.IsNumeric(user))
            {
                m_userCollection.Remove(TypeConverter.ToInteger(user));
            }
            else
            {
                m_userCollection.Remove(TypeConverter.ToString(user));
            }
        }
 public void DeleteUser(string username)
 {
     if (string.IsNullOrEmpty(username))
     {
         return;
     }
     try
     {
         SPUser user = GetUserObject(username);
         if (user == null)
         {
             return;
         }
         using (SPWeb website = GetWebSite())
         {
             SPUserCollection varUsers = website.SiteUsers;
             varUsers.Remove(username);
             website.Update();
         }
     }
     catch (Exception ex)
     {
         var log = new AppEventLog(AppException.ExceptionMessage(ex, "DeleteUser", "ClsHelper"));
         log.WriteToLog();
     }
 }