using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Linq;
using System.Collections.Generic;
namespace ConsoleApplication8
{
class Program
{
static void Main(string[] args)
{
List<Customer> customers = CreateCustomerList();
// Find customer by first name
IEnumerable<Customer> result = from customer in customers//指定范围变量和数据源 customers
where customer.FirstName == "Donna" select customer;
List<Customer> cachedResult = result.ToList<Customer>();//如果你想缓存结果,这样它就可以加工后无需重新制作查询,
//你可以用ToList方法或ToArray()方法来保存结果的副本。
Console.WriteLine("FirstName == "Donna"");
foreach (Customer customer in result)
{
Console.WriteLine(customer.ToString());
}
customers[3].FirstName = "Donna";
Console.WriteLine("FirstName == "Donna" (take two)");
foreach (Customer customer in result)
{
Console.WriteLine(customer.ToString());
Console.ReadLine();
}//将第四个对象的First name改为Donna并输出
}
private static List<Customer> CreateCustomerList()
{
List<Customer> customers = new List<Customer>
{ new Customer
{ FirstName = "Orlando",LastName = "Gee", EmailAddress = "orlando0@adventure-works.com"},
new Customer { FirstName = "Keith", LastName = "Harris", EmailAddress = "keith0@adventure-works.com" },
new Customer { FirstName = "Donna", LastName = "Carreras", EmailAddress = "donna0@adventure-works.com" },
new Customer { FirstName = "Janet", LastName = "Gates", EmailAddress = "janet1@adventure-works.com" },
new Customer { FirstName = "Lucy", LastName = "Harrington", EmailAddress = "lucy0@adventure-works.com" } };
return customers;
}
}
}
public class Customer
{
public string FirstName { get; set; }
public string LastName { get; set; }
public string EmailAddress { get; set; }
// Overrides the Object.ToString() to provide a
// string representation of the object properties.
public override string ToString()
{
return string.Format("{0} {1}
Email: {2}",
FirstName, LastName, EmailAddress);
}
}