LINQ Generic GroupBy And SelectBy With Method Syntax - entity-framework

Question

I'm trying to make it generic but didn't succeed. It doesnt get related User entity.
return from transactions in context.Transaction
where transactions.Date.Month == date.Month && transactions.Date.Year == date.Year
join users in context.UserProfile on transactions.UserID equals users.UserID
orderby transactions.MonthlyTotalExperiencePoint
group transactions by transactions.UserID into groupedList
select groupedList.First()).Take(50).ToList();
I've tried that:
public async Task<List<object>> GetAllGroup<TReturn, TOrderKey, TGroupKey>(Expression<Func<IGrouping<TGroupKey, TEntity>, TReturn>> selectExp,
Expression<Func<TEntity, bool>> whereExp,
Expression<Func<TEntity, TOrderKey>> orderbyExp,
bool descending,
int top,
Expression<Func<TEntity, TGroupKey>> groupByExp,
params Expression<Func<TEntity, object>>[] includeExps)
{
var query = DbSet.Where(whereExp);
query = !descending ? query.OrderBy(orderbyExp) : query.OrderByDescending(orderbyExp);
if (includeExps != null)
query = includeExps.Aggregate(query, (current, exp) => current.Include(exp));
return await query.GroupBy(groupByExp).Select(selectExp).Take(top).ToListAsync();
}
It gives error at usage:
var item = await transactionRepository.GetAllGroup(x => x.FirstOrDefault(), x => x.Date != null, x => x.MonthlyTotalExperiencePoint, true, 50, x => x.MonthlyTotalExperiencePoint, x => x.User);