How to make a SUM of Dictionary Value nested into a list with LINQ?

I have a product object declared as :

Product {
   int ProductID;
   string ProductName;
   int ProductTypeID;
   string ProductTypeName;
   int UnitsSold
   Dictionary <string, int> UnitsSoldByYear;
}

I want to make a sum on UnitsSold and UnitsSoldByYear properties with a Linq query but I didn't k开发者_运维百科now how to make this kind of sum on a dictionary ! Here is my begining linq query code :

var ProductTypeSum = from i in ProductsList
                     group i by new { i.ProductTypeID, i.ProductTypeName} into pt
                     select new
                         {
                             ProductTypeID= pt.Key.ProductTypeID,
                             ProductTypeName= pt.Key.ProductTypeName,
                             UnitsSoldSum= pt.Sum(i => i.UnitsSold),
                             // How to make a Dictionary sum here
                            }

Thank you for your help !

To sum your inner dictionary just do:

DictSum = pt.Select(x => x.UnitsSoldByYear.Values.Sum()).Sum()

or equally:

DictSum = pt.Sum(x => x.UnitsSoldByYear.Values.Sum())

EDIT:

according to the OP comment, this creates a dictionary with the sum by each key:

DictSum = pt.SelectMany(kvp => kvp.UnitsSoldByYear)
            .GroupBy(kvp => kvp.Key)
            .ToDictionary(grp => grp.Key,grp => grp.Sum(kvp => kvp.Value))