Linq:从List列表中查询数据(Where查询)

 

获取List<Customer> customerList的函数见：http://www.cnblogs.com/yf2011/p/3369927.html

输出List中Berlin城市的Customer信息和该Customer订单

public void GetCustomerOrderByCity()
            {
                List<Customer> customers = GetList();

                var waCustomers =
                    from cust in customers
                    where cust.City== "Berlin"
                    select cust;

                foreach (var customer in waCustomers)
                {
                    Console.WriteLine("Customer {0}: {1}", customer.CustomerID, customer.CompanyName);
                    foreach (var order in customer.Orders)
                    {
                        Console.WriteLine("  Order {0}: {1}", order.OrderID, order.OrderDate);
                    }
                }
            }

多条件查询

public void GetCustomerOrderByCId()
            {
                List<Customer> customers = GetList();

                var waCustomers =
                    from cust in customers
                    where cust.CId>1&&cust.CId<5
                    select cust;

                foreach (var customer in waCustomers)
                {
                    Console.WriteLine("Customer {0}: {1}", customer.CustomerID, customer.CompanyName);
                    foreach (var order in customer.Orders)
                    {
                        Console.WriteLine("  Order {0}: {1}", order.OrderID, order.OrderDate);
                    }
                }
            }

 

            [Description("查询值的长度比索引小的项.")]
            public void GetStrInList()
            {
                string[] digits = { "zero", "one", "two", "three", "four", "five", "six", "seven", "eight", "nine" };
                var shortDigits = digits.Where((digit, index) => digit.Length < index);
                foreach (var d in shortDigits)
                {
                    Console.WriteLine(d);
                }
                Console.ReadLine();
            }

在上述示例中 five长度为4索引为5，six长度为3索引为6，seven长度为5索引为7，eight长度为5索引为8，nine长度为4索引为9.输出结果为：
five
six
seven
eight
nine

 

内容源自：http://code.msdn.microsoft.com/101-LINQ-Samples-3fb9811b