//--------------------------------------------------------------------------------    
//1. In Clausing using a LIST
//--------------------------------------------------------------------------------
List<decimal> OrderList = new List<decimal>();    
OrderList.Add(10248);
OrderList.Add(10250);
var OrderListArr = OrderList.ToArray();

var CustOrders = from o in Orders
                 where OrderListArr.Contains(o.OrderID)
                 select o;
    
CustOrders.Dump();

//--------------------------------------------------------------------------------
//2. In Clause using a LINQ statement. Get Customer Orders from Brazil customers
//--------------------------------------------------------------------------------
var BrazilOrders = from o in Orders
                   where (from c in Customers
                         where c.Country.Contains("Brazil")
                         select c.CustomerID).Contains(o.CustomerID)
                   select o;
BrazilOrders.Dump();