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Cannot convert expression type 'System.Linq.IQueryable to return type 'System.Threading.Tasks.Task<System.Collections.Generic.IEnumerable

byMR

March 6, 2023

I’m trying to join 2 tables and return data that meet a specific condition. However, I get this error instead

Cannot convert expression type ‘System.Linq.IQueryable<TicketBooking.Data.DataModel.Flight>’ to return type ‘System.Threading.Tasks.Task<System.Collections.Generic.IEnumerable<TicketBooking.Data.DataModel.Flight>>’

Here is the red squiggle error code, my intention is to return the flight that has the specific date.

public async Task<IEnumerable<Flight>> GetFlightByDate(DateTime date)
    {
        var query = from f in _context.Flights
            join fs in _context.FlightSchedules
                on f.ScheduleId equals fs.Id
                    where fs.DepartureTime == date
            select new 
            {
                flight = f
            };

        return query;
    }

>Solution :

You need .ToListAsync() to execute the query.

While you have modify your query as your current query return list of anonymous type but not list of Flight.

public async Task<IEnumerable<Flight>> GetFlightByDate(DateTime date)
{
    var query = from f in _context.Flights
        join fs in _context.FlightSchedules
            on f.ScheduleId equals fs.Id
        where fs.DepartureTime == date
        select f;

    return await query.ToListAsync();
}