Perform calculation inside select statement in LINQ

Question

I have a situation where i have to calculate percentage of two values for example

IEnumerable<RenewalModel> result = 
    from r in renewalLists
    group r by r.CityID into grpCity
    select new RenewalModel
    {
        CityID = grpCity.Key,
        City = (from g in grpCity where g.CityID == grpCity.Key select g.City).First().Trim(),
        PotentialRenewalCount = (from g in grpCity where g.CityID == grpCity.Key select g.PotentialRenewalCount).Sum(),
        PotentialRenewalSQRT = (from g in grpCity where g.CityID == grpCity.Key select g.PotentialRenewalSQRT).Sum(),
        desiredCalucation=   (PotentialRenewalCount/PotentialRenewalCount)*100,
        RENEWALCOUNT = (from g in grpCity where g.CityID == grpCity.Key select g.RENEWALCOUNT).Sum(),
        RENEWALSQRT = (from g in grpCity where g.CityID == grpCity.Key select g.RENEWALSQRT).Sum()
    };

and my calculation should be like this

(PotentialRenewalCount/PotentialRenewalCount)*100

as i have described it inside the select statement.

i even tried this query but i get the 0 as result

 IEnumerable<RenewalModel> result =
            (from r in renewalLists
            group r by r.CityID into grpCity
            select new RenewalModel
            {
                CityID = grpCity.Key,
                City = (from g in grpCity where g.CityID == grpCity.Key select g.City).First().Trim(),
                PotentialRenewalCount = (from g in grpCity where g.CityID == grpCity.Key select g.PotentialRenewalCount).Sum(),
                PotentialRenewalSQRT = (from g in grpCity where g.CityID == grpCity.Key select g.PotentialRenewalSQRT).Sum(),
                RENEWALCOUNT = (from g in grpCity where g.CityID == grpCity.Key select g.RENEWALCOUNT).Sum(),
                RENEWALSQRT = (from g in grpCity where g.CityID == grpCity.Key select g.RENEWALSQRT).Sum()
            }).select(r => new RenewalModel
            {
                desiredCalucation = (r.PotentialRenewalCount / r.PotentialRenewalCount) * 100,
                CityID = r.CityID,
                City = r.City,
                PotentialRenewalCount = r.PotentialRenewalCount,
                PotentialRenewalSQRT = r.PotentialRenewalSQRT,
                RENEWALCOUNT = r.RENEWALCOUNT,
                RENEWALSQRT = r.RENEWALSQRT
            });

for some reason or another desiredCalucation variable is giving me 0 as result.

any help is appreciated. Thank you

Answer 1

For this purpose, use the LINQ let operator.

In general, I would recommend to split your big LINQ statement on several smaller ones. Otherwise, it will be very painful to debug this later.