Viewmodel with conditional aggregation (Sums) - asp.net-mvc

Question

I have a viewmodel
public class RecTotal
{
public string PayType { get; set; }
public decimal TotalPrice { get; set; }
public string Category { get; set; }
}
public class ReconcileViewModel
{
public IEnumerable<RecTotal> RecTotals { get; set; }
public IEnumerable<RecInvoiceLineItem> LineItems { get; set; }
}
How do I create sums of the categories and create a new RecTotal record for each one. Ex:
ReconcileViewModel VM = new ReconcileViewModel();
foreach(POSItemCategory cat in db.POSItemCategories)
{
recLineItems.Where(p => p.Category == cat.ID).Sum(p => p.InvPrice);
}
The end result i'm looking for is something like
VM.RecTotal.Add(Sum(TotalPrice), foreach(Category)
I know I'm close but I just cant quite get it.

Answer 1

I found a way to do this, but it is "Ugly" in my opinion and there has to be a better way to do it....
var test = new List<RecTotal>();
foreach (POSItemCategory cat in db.POSItemCategories)
{
test.Add(new RecTotal
{
NumberOfItems = recLineItems.Where(p => p.Category == cat.ID).Count(),
TotalPrice = recLineItems.Where(p => p.Category == cat.ID).Sum(p => p.InvPrice),
PayType = "All",
Category = cat.Name,
NumberOfInvoices = recLineItems.Where(p => p.Category == cat.ID).Select(p => p.InvID).Distinct().Count()
});
};
VM.RecTotals = test;
Please let me know if there is a better way of doing this.

Answer 2

you can try this
var testdata = new List<RecTotal>();
testdata = recLineItems.Where(x => db.POSItemCategories.Select(a=>a.ID).Contains(x.Category))
.GroupBy(x => x.Category)
.Select(
x =>
new RecTotal()
{
Category = x.Key,
PayType = "All",
TotalPrice = x.Sum(z => z.InvPrice),
NumberOfItems = x.Count(),
NumberOfInvoices = x.Select(p => p.InvID).Distinct().Count()
}).ToList();