Sum field in sub query in Linq giving Cannot Assign Method error - linq

Question

I want to be able to group a sub-linq query, but LinqPad is giving an error at this line:
ratetocharge =rtc.rate.Sum
The error is: Cannot assign method group to anonymous type property.
Could anyone advise what I should enter in that line, to give me a sum of the rate within the rates table?
Thank you,
Mark
var mtgRooms = RoomUnit
.Where(r => r.building_id==1)
.GroupBy(p => p.Type)
.Select(g => new
{
TypeName = g.Key.type_name,
TypeID = g.Key.type_id,
TypeCount = g.Count(),
rates = rates
.Select ( rtc =>
new
{
occ = rtc.occ,
ratetocharge =rtc.rate.Sum // this is the line which errors
}
)
.GroupBy(pe => pe.occ)
}
);
mtgRooms.Dump();
EDIT: To add further detail
Tables:
Table RoomUnit
type_id (key - int)
type_name (string - eg. large room, small room, medium room)
building_id (int - denotes a number of buildings this room could be within)
Rates
rate_id
type_id (foreign key to RoomUnit)
occ (type of rate - ie. Desk, FullRoom)
The idea is I want to provide a model that looks like this:
Type of Room
Number of Types of Room available
Type of Occ/Desks available
Sum of Rate (rate to charge) for each type of desk
Currently what shows is:
LargeRoom, Type 3049, Type Count 18 (or whatever is available)
occ FullRoom, ratetocharge 250, numOfOcc 1
occ FullRoom, ratetocharge 250, numOfOcc 1
occ FullRoom, ratetocharge 250, numOfOcc 1
occ Single Desk, ratetocharge 45, numOfOcc 1
occ Single Desk, ratetocharge 45, numOfOcc 1
SmallRoom, Type 3093, Type Count 4 (or whatever is available)
occ FullRoom, ratetocharge 150, numOfOcc 1
occ FullRoom, ratetocharge 150, numOfOcc 1
occ Single Desk, ratetocharge 45, numOfOcc 1
occ Single Desk, ratetocharge 45, numOfOcc 1
occ Single Desk, ratetocharge 45, numOfOcc 1
Whereas I would like the model to sum the rateToCharge by Occ in the sub table, eg:
LargeRoom, Type 3049, Type Count 18 (or whatever is available)
occ FullRoom, ratetocharge 750, numOfOcc 3
occ Single Desk, ratetocharge 90, numOfOcc 2
SmallRoom, Type 3093, Type Count 4 (or whatever is available)
occ FullRoom, ratetocharge 300, numOfOcc 2
occ Single Desk, ratetocharge 135, numOfOcc 3

Answer 1

change ratetocharge =rtc.rate.Sum to ratetocharge =rtc.rate.Sum(). Using Sum the compiler thinks you are trying to make the ratetocharge variable assigned the method group; the set of methods (including overloads) of the Sum method. Instead you need to make the call Sum() which actually calls the method.
--- Edit --- looking at your further information, I am going with this as the way to implement
var mtgRooms = RoomUnit
.Where(r => r.building_id==1)
.GroupBy(p => p.Type)
.Select(g => new
{
TypeName = g.Key.type_name,
TypeID = g.Key.type_id,
TypeCount = g.Count(),
rates = Rates.Where(rt => rt.type_id == g.type_id).GroupBy(rt => rt.occ)
.Select(proj => new {
occ = proj.Key,
ratetocharge = proj.Sum(s => s.rate),
numOfOcc = proj.count())
})
}
);