How can I get the count in linq?

Not sure I am understanding exactly + making some assumptions but here is an example linq query that produces a count based on some arbitrary selection criteria (id=2 and price greater than 100)...

int count = (from p in tsgdbcontext.Products
             where p.productid == 2 && p.productprice > 100
             select p).Count();

Use GroupBy with a key that contains your grouping properties. Then select out the key properties along with the count of each from the grouping.

var query = tsgdbcontext.Products
                        .GroupBy(p => new {
                            p.ProductId,
                            p.ProductName,
                            p.ProductPrice
                         })
                        .Select(g => new {
                            g.Key.ProductId,
                            g.Key.ProductName,
                            g.Key.ProductPrice,
                            Available = g.Count()
                        });