public IQueryable Find method()

bh81 · July 13th, 2011, 07:16 AM

I am trying to enhance the Iqueryable Find method, very similar to:
public IQueryable<Dinner> FindUpcomingDinners()
{
return from dinner in db.Dinners
where dinner.EventDate > DateTime.Now
orderby dinner.EventDate
select dinner;
}
in NerdDinner.

In my GymAttendance, AttnRepository.cs (very similar to DinnerRepository.cs in NerdDinner), I am trying to query the database table on a selected date and the Time from/To, which I have as a float datatype.

Code:

        public IQueryable<Attendance> FindAttendance(DateTime SelDate, float SelTimeFrom, float SelTimeTo)
        {
            return from attendance in db.Attendances
                   where attendance.GA_Date == SelDate && SelTimeFrom >= attendance.GA_Time_From && SelTimeTo <= attendance.GA_Time_To
                   orderby attendance.GA_Date, attendance.GA_Time_From
                   select attendance;
        }

it gives me error:

Quote:

'>=' cannot be applied to operands of type 'float' and 'string'

on both

Quote:

SelTimeFrom >= attendance.GA_Time_From

and

Quote:

SelTimeTo <= attendance.GA_Time_To

Is this the right way to query multiple fields in a table? What could I do to query the time, which I store as float datatype?

Thanks in advance.

Imar · July 13th, 2011, 07:24 AM

Quote:

Is this the right way to query multiple fields in a table? What could I do to query the time, which I store as float datatype?

Yes, but it seems that you're not storing them as floats, but as strings. Since the SelTimeFrom and SelTimeTo parameters are typed as floats, my guess is that attendance.GA_Time_From is actually a string, not a float.

Hope this helps,

Imar

bh81 · July 13th, 2011, 07:47 AM

Thank you Imar again. I was just about to post my findings but you beat me to it. Yes, you are absolutely right, the
public float GA_Time_From { get; set; }
public float GA_Time_To { get; set; }
was indeed string before.

Many thanks again Imar. You're so efficient.