Can't add/sum string values in IEnumerable - entity-framework

Question

The ultimate goal is to display a GrandTotal column using Highcharts. The GrandTotal should be the sum of TotalAmount for a given Offer id. TotalAmount is a string and the values are like $10.00 or 10.00. GrandTotal is an int, but could easily be changed. Here is what I have done so far.
Step 1) Convert the two IEnumerable lists into their ViewModel counterparts. I set GrandTotal to 0 here because I don't know the amount.
var offersConvert = offers
.Select(o => new OfferSummaryViewModel
{
Id = o.Id,
Name = o.Name,
Created = o.Created,
Shares = o.Shares,
Redemptions = o.Redemptions,
GrandTotal = 0
})
.ToList();
var sharedOffersConvert = sharedOffers
.Select(s => new SharedOfferViewModel
{
OfferId = s.OfferId,
//TotalAmount = s.TotalAmount.Replace("$", string.Empty).Replace(",", string.Empty).Trim()
TotalAmount = s.TotalAmount
})
//.Where(i => i.TotalAmount != null)
.ToList();
Step 2) Join the two lists on the Id of the Offer.
var data = offersConvert
.Join(sharedOffersConvert,
o => o.Id,
s => s.OfferId,
(o, s) => new { offersConvert = o, sharedOffersConvert = s })
.Select(o => new
{
Id = o.offersConvert.Id,
Created = o.offersConvert.Created,
Shares = o.offersConvert.Shares,
Redemptions = o.offersConvert.Redemptions,
Name = o.offersConvert.Name,
OfferId = o.sharedOffersConvert.OfferId,
TotalAmount = o.sharedOffersConvert.TotalAmount,
//GrandTotal = Convert.ToInt32(o.sharedOffersConvert.TotalAmount.Replace("$", string.Empty).Replace(",", string.Empty).Trim())
//GrandTotal = Convert.ToInt32(Convert.ToDouble(o.sharedOffersConvert.TotalAmount, CultureInfo.InvariantCulture))
})
//.Where(o => o.Id == o.OfferId)
.OrderBy(o => o.Created.Add(offset))
.ToList();
As you can tell, I've tried to remove any dollar signs and commas. I've even tried to trim white space in order to get clean data. I am then trying to convert the strings to int values, so I can sum them. Nothing seems to work. I've even tried .GroupBy and other methods (see below). At least with .GroupBy I can get to the .Sum operator. With the other method I run into issues when I can't convert int into ToList(), so I have to try and convert ToString().
.Where(o => o.Id == o.OfferId)
.GroupBy(g => g.Id)
.Select(x => new { GrandTotal = x.Sum(o => o.TotalAmount) })
ERROR in above: can't convert TotalAmount to decimal
.Where(i => i.Id == i.OfferId)
.Sum(i => Convert.ToInt32(Convert.ToDouble(i.TotalAmount, CultureInfo.InvariantCulture)
)).ToString()
Does anyone know how I can add/sum the string values in TotalAmount to get a GrandTotal per Offer id?
Any help us much appreciated. Thanks!
UPDATE: This works, but I really don't understand why and I don't think it is very clean. I really couldn't find many examples where people were joining two lists together and summing one of the columns. This seems pretty common to me, but perhaps it is not.
var data = (from o in offersConvert
join s in sharedOffersConvert on o.Id equals s.OfferId
orderby o.Created.Add(offset)
let k = new
{
Id = o.Id,
Name = o.Name,
Created = o.Created,
Shares = o.Shares,
Redemptions = o.Redemptions
}
group s by k into totals
select new
{
OfferId = totals.Key.Id,
Name = totals.Key.Name,
Created = totals.Key.Created,
Shares = totals.Key.Shares,
Id = totals.Key.Id,
Redemptions = totals.Key.Redemptions,
GrandTotal = totals.Sum((s => s.TotalAmount == null ? Decimal.Zero : Decimal.Parse(s.TotalAmount, NumberStyles.Currency)))
})
.ToList();

Answer 1

You can use
Decimal.TryParse("$10.00", NumberStyles.Currency, CultureInfo.CurrentCulture, out var res);
Or in the context of your LINQ,
GrandTotal = Decimal.Parse(o.sharedOffersConvert.TotalAmount, NumberStyles.Currency)
if o.sahredOffersConvert.TotalAmount may be null,
GrandTotal = (o.sharedOffersConvert.TotalAmount ==null) ? Decimal.Zero : Decimal.Parse(o.sharedOffersConvert.TotalAmount, NumberStyles.Currency)

Answer 2

I'm still puzzled why everyone lately has this odd fascination with the Lambda syntax. And that seems to have been only one of several means you've used to make this more complicated than necessary:
var data = (from o in offers
join s in sharedOffers on o.Id equals s.OfferId
orderby o.Created.Add(offset)
select new
{
Id = o.Id,
Created = o.Created,
Shares = o.Shares,
Redemptions = o.Redemptions,
Name = o.Name,
OfferId = o.OfferId,
TotalAmount = Decimal.Parse(o.TotalAmount, NumberStyles.Currency)
})
.ToList();
Further, as offset seems to be a constant (for the life of this query), adding it to Created isn't going to affect the ordering, and that bit can be removed.
And, since it appears your final output is just the grand totals, it can be reduced further to:
var data = (from o in offers
join s in sharedOffers on o.Id equals s.OfferId
orderby o.Created
group Decimal.Parse(o.TotalAmount, NumberStyles.Currency) by o.id into totals
select new
{
Id = totals.Key,
GrandAmount = totals.Sum()
})
.ToList();
UPDATE: Putting back what I took out... This should work (I don't have your tables, so I can't test it)
var data = (from o in offers
join s in sharedOffers on o.Id equals s.OfferId
orderby o.Created.Add
group o by o.Id into totals
let item = totals.First()
select new
{
Id = item.Id,
Created = item.Created,
Shares = item.Shares,
Redemptions = o.Redemptions,
Name = item.Name,
OfferId = item.OfferId,
GrandTotal = totals.Sum(t=>Decimal.Parse(t.TotalAmount, NumberStyles.Currency))
})
.ToList();