Question

I have the following code for Customers and their orders. I want to list all the customerID and the corresponding count of orders. How do I achieve it using LINQ?

Note: I am new to LINQ and var.

protected void Page_Load(object sender, EventArgs e)
{

    List<Order> orderListForCus1 = new List<Order>();
    Order ord1 = new Order(1, new DateTime(2011, 9, 1));
    Order ord2 = new Order(1, new DateTime(2011, 8, 1));
    orderListForCus1.Add(ord1);
    orderListForCus1.Add(ord2);

    Customer cus1 = new Customer();
    cus1.CustomerID = 1;
    cus1.OrderList = orderListForCus1;


    List<Customer> customerRecordsBook = new List<Customer>();
    customerRecordsBook.Add(cus1);


    var orderCounts = from c in customerRecordsBook
                      select new { c.CustomerID, OrderCount = c.OrderList.Count() };



}

Answer 1

You’re almost there.
You can loop over your anonymously-typed objects just like any other objects:

foreach (var o in orderCounts) {
    Response.Write(o.CustomerID + ": " + o.OrderCount + " orders");
}

Note that o must be declared as var, since the type has no name that you can use.

---

In your case, you don’t actually need LINQ; you can just use the List<T> directly:

foreach (var c in customerRecordsBook) {
    Response.Write(c.CustomerID + ": " + c.OrderList.Count + " orders");
}