private IQueryable <T> getQuery()
        {
            IContextMetaData <UserManagementDbContext> contextMeta = _ambientScopeLocator.GetWithMetaData <UserManagementDbContext>() ?? throw new InvalidOperationException("No open ambient DbContext was found.");

            var dbSet = contextMeta.DbContext.Set <T>();

            return(contextMeta.IsReadOnly ? dbSet.AsNoTracking() : dbSet);
        }