C#细节之lambda,linq,匿名方法

最新推荐文章于 2022-04-22 23:36:17 发布

转载最新推荐文章于 2022-04-22 23:36:17 发布 · 143 阅读

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原文链接：http://www.cnblogs.com/pangxiaoliang/archive/2009/07/28/1530654.html

本文通过具体的C#代码示例介绍了Lambda表达式的使用方法及其与匿名方法的区别，并展示了如何利用LINQ进行数据筛选及转换操作。

看代码，得永生
不再解释，很容易的，我没有仔细研究过，在此记下，以后深入研究。

using System;
using System.Collections.Generic;
using System.Collections;
using System.Linq;
using System.Text;

namespace Landpy
{
    class Starter
    {
        delegate int Add(int i, int j);
        delegate bool Compare(int i, int j);
        delegate void NoNameMethod(string name);
        static void Main()
        {
            Add add = (x, y) => x + y;
            Console.WriteLine(add.Invoke(1, 2));
            Compare compare = (i, j) => i == j;
            Console.WriteLine(compare.Invoke(1, 2));
            Console.WriteLine(compare.Invoke(1, 1));
            NoNameMethod noNameMethod =
                delegate(string name)
                {
                    Console.WriteLine(String.Format("Hello {0}!", name));
                };
            Action<int> hello = delegate(int i)
            {
                for (int j = 0; j < i; j++)
                {
                    Console.WriteLine("Hello");
                }
            };
            noNameMethod.Invoke("Landpy");
            hello.Invoke(3);

            string[] names = { "++landpy", "pxl", "ljc", "baby" };
            //lambda的写法
            var quereynamestwo = names.Where(n => n.Length == 3).Select(n => n.Substring(2));//.Select(n => n.Name);

            //linq的写法
            var quereynames = from n in names
                              where n.Length == 3
                              select n;

            foreach (string name in quereynames)
            {
                Console.WriteLine(name);
            }

            foreach (string name in quereynamestwo)
            {
                Console.WriteLine(name);
            }

            ArrayList employees = new ArrayList();

            for (int i = 0; i < 10; i++)
            {
                Employee employee = new Employee();
                employee.Name = "Name" + i.ToString();
                employee.Age = i;
                employees.Add(employee);
            }

            Employee[] employeesArray = (Employee[])employees.ToArray(typeof(Employee));

            var es = employeesArray.Where(n => n.Age > 4);
            foreach (Employee employeeTmp in es)
            {
                Console.WriteLine(employeeTmp.Name);
            }
        }
    }

    class Employee
    {
        public string Name
        {
            get;
            set;
        }

        public int Age
        {
            get;
            set;
        }
    }
}

转载于:https://www.cnblogs.com/pangxiaoliang/archive/2009/07/28/1530654.html