linq query repeated columns in a list

Question

I have a table similar to the one below.

Branch      Dept        Product ID  Product Val Product Date
Branch 1        Dept 1      ID 1        1       5/23/2013
Branch 1        Dept 1      ID 2        1       5/23/2013
Branch 1        Dept 2      ID 3        1       5/23/2013
Branch 2        Dept 11     ID 4        1       5/23/2013
Branch 2        Dept 11     ID 5        1       5/23/2013
Branch 2        Dept 11     ID 6        1       5/23/2013
Branch 3        Dept 21     ID 7        1       5/23/2013

I am trying to use LINQ(am a rookie to LINQ) to load this as a collection of objects into an object like:

Products = { Branch1 { Dept1 {ID1,ID2}, 
                       Dept2 {ID3}}, 
             Branch2 { Dept11 {ID4, ID5, ID6}}, 
             Branch3 { Dept21 {ID7 }
           }

And I have trying bit hard working overnight but could not get the right solution. So far I have achieved the following code;

var branches = (from p in ProductsList
    select p.Branch).Distinct();
var products = from s in branches
    select new
    {
        branch = s,
        depts = (from p in ProductsList
            where p.Branch == s
            select new
            {
                dept = p.Dept,
                branch = s,
                prod = (from t in ProductsList
                    where t.Branch = s
                    where t.Dept == p.Dept
                    select t.ProductID)
            })
    };

where ProductsList is the list object of the whole table date List

Any help at the earliest is much appreciated. Thanks in advance!

Answer 1

I would go for soemthing like that if you really wanna use linq.

Somethimes, a few foreach are much clearer !

var myDic = ProductList
                .GroupBy(m => m.Branch)
                .ToDictionary(
                    m => m.Key,
                    m => m.GroupBy(x => x.Dept)
                          .ToDictionary(
                              x => x.Key,
                              x => x.Select(z => z.ProductId)));

result will be a

Dictionary<string, Dictionary<string, IEnumerable<string>>>

where first dictionary Key is Branch, inner dictionary key is Dept, and string list are ProductId

which seem to correpond to your wanted result.

Answer 2

Something like this, maybe?

Products.
    .Select(prop => prop.Branch)
    .Distinct()
    .Select(b => new 
    {
        Branch = b,
        Departments = Products
            .Where(p => p.Branch == b)
            .Select(p => p.Dept)
            .Distinct()
            .Select(d => new 
            {
                Products = Products
                    .Where(p => p.Department == d)
                    .Select(p => p.ProductID)
                    .Distinct()
            })
    })