Linq: GroupBy, Sum and Count

Question

I have a collection of products

public class Product {

   public Product() { }

   public string ProductCode {get; set;}
   public decimal Price {get; set;          


        

Answer 1

sometimes you need to select some fields by FirstOrDefault() or singleOrDefault() you can use the below query:

List result = Lines
    .GroupBy(l => l.ProductCode)
    .Select(cl => new Models.ResultLine
            {
                ProductName = cl.select(x=>x.Name).FirstOrDefault(),
                Quantity = cl.Count().ToString(),
                Price = cl.Sum(c => c.Price).ToString(),
            }).ToList();