C#面向对象22 委托事件反射

1.委托的定义：声明委托类型(返回值和参数，命名空间中)；定义委托对象

  （把委托想象成函数中的占位符~因为你并不确定调用哪个函数~）

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

namespace @delegate
{
    public delegate void DelSayHi(string name);
    class Program
    {
        static void Main(string[] args)
        {
            //1.委托的定义：声明委托类型(返回值和参数)；定义委托对象；
            //DelSayHi del = SayChinese;
            //del("22");
            //DelSayHi del = delegate(string name){Console.WriteLine("吃了么?" + name);};
            //del("22");
            //DelSayHi del = (name) => { Console.WriteLine("吃了么?" + name); };
            //del("112233");
            
            //2
            Test("22", SayChinese);
            //3 匿名函数
            Test("222", delegate(string name) { Console.WriteLine("吃了么?" + name); });
            //4 lamda表达式
            Test("222", (name) => { Console.WriteLine("吃了么?" + name); });
            
            Console.ReadKey();
        }

        public static void Test(string name, DelSayHi del)
        {
            //调用
            del(name);
        }
        public static void SayChinese(string name)
        {
            Console.WriteLine("吃了么?" + name);
        }
        public static void SayEnglish(string name)
        {
            Console.WriteLine("Nice to meet you" + name);
        }

    }
}

2. 匿名函数 lamda表达式

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

namespace delegate2
{
    public delegate string DelString(string name);
    class Program
    {
        static void Main(string[] args)
        {

            string[] names = { "abCDefG", "HIJKlmnOP", "QRsTuW", "XyZ" };

            //转大写 lamda
            DealString(names, (name) => { return name.ToUpper(); });
            //转大写 匿名函数
            DealString(names, delegate(string name) { return name.ToUpper(); });

            foreach (string  item in names)
            {
                Console.WriteLine(item);
            }
            Console.ReadKey();
        }

        static void DealString(string [] names ,DelString del2)
        {
            for (int i = 0; i < names.Length; i++)
            {
                names[i] = del2(names[i]);
            }
        }

    }
}

3.求取任意数组的最大值

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

namespace delegate3
{
    public delegate int DelCompare(object t1,object t2);
    class Program
    {
        static void Main(string[] args)
        {
            object[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
            object[] strings = { "1", "12", "123" };
            object[] persons = { new person(13,"22"),new person(14,"33"),new person(15,"44")};

            //int 数组
            object i =GetMax(nums,delegate(object max,object num){
              int IntMax =(int)max;
              int IntNum=(int)num;
              int result=IntMax-IntNum;
              return result;
            });
            Console.WriteLine(i);

            //string 数组
            object j = GetMax(strings, (max, num) =>
            {
                string s_max = (string)max;
                string s_num = (string)num;
                return s_max.Length - s_num.Length;
            });
            Console.WriteLine(j);

            //对象 数组
            object oldPserson = GetMax(persons, (max, num) =>
            {
                person s_max = (person)max;
                person s_num = (person)num;
                return s_max.Age - s_num.Age;
            });
            Console.WriteLine(((person)oldPserson).Name);
            Console.ReadKey();
        }

        static object GetMax(object [] nums,DelCompare del)
        {
            object max = nums[0];
            for (int i = 0; i < nums.Length; i++)
            {
                if (del(max,nums[i]) < 0)
                    max = nums[i];
            }
            return max;
        }
    }

    class person
    {
        public person(int _age, string _name)
        {
            Age = _age;
            Name = _name;
        }
        public int Age { get; set; }
        public string Name{get;set;}
    }
}

4.泛型委托

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

namespace delegate4
{
    public delegate int DelCompare<T>(T t1, T t2);
    class Program
    {
        static void Main(string[] args)
        {
            int[] nums = { 1, 2, 3, 4, 5, 6, 7, 8, 99 };

            int i = GetMax<int>(nums, (max, num) => {
                return max - num;
            });

            Console.WriteLine(i);
            Console.ReadKey();
        }

        static T GetMax<T>(T[] nums, DelCompare<T> del)
        {
            T max = nums[0];
            for (int i = 0; i < nums.Length; i++)
            {
                if (del(max, nums[i]) < 0)
                    max = nums[i];
            }
            return max;
        }
    }
}

5.窗体之间的传值

Form1.cs:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            Form2 fm2 = new Form2();
            fm2.showtt = ShowLab;
            fm2.Show();
        }
        private void ShowLab(string tt)
        {
            this.label1.Text = tt;
        }
    }
}

Form2.cs:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace WindowsFormsApplication1
{
    public delegate void ShowDele(string tt);
    public partial class Form2 : Form
    {
        public ShowDele showtt;
        public Form2()
        {
            InitializeComponent();
        }
        private void button1_Click(object sender, EventArgs e)
        {
            string temp = this.textBox1.Text.Trim();
            showtt(temp);
        }
    }
}

6.事件 （安全类型的委托！）

**事件只能在声明事件的那个类中被调用！类以外只能注册这个事件！

 类中声明事件，调用事件：

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

namespace _06使用Winform应用程序模拟事件
{

    public delegate void DelPlayOver();
    class PlayMusic
    {
        public event DelPlayOver Del;//声明事件不需要写()

        //音乐播放的名字
        public string Name { get; set; }

        public PlayMusic(string name)
        {
            this.Name = name;
        }

        public void PlaySongs()
        {
            Console.WriteLine("正在播放" + this.Name);
            //模拟播放了三秒钟
            Thread.Sleep(3000);

            if (Del != null)
            {
                //当播放完成后  执行一个事件
                Del();//直接调用“事件”
            }
        }
    }
}

类的外面，（另一个类中注册事件）：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace _06使用Winform应用程序模拟事件
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            PlayMusic p = new PlayMusic("忐忑");//创建对象 开始播放音乐
            p.Del += Test;//注册事件
            p.PlaySongs();//开始播放音乐
        }

        //事件要执行的函数
        void Test()
        {
            //Console.WriteLine("播放完成了！！！！");
            MessageBox.Show("播放完成了!!!");
        }
    }
}

7.反射

a.理解程序集：包含资源文件，类型元数据，exe，dll.

   程序集可以看做是一堆相关类的打一个包，相当于java中的jar包。

b.反射：动态获取一个程序集中的元数据的功能！

c.AssemblyInfo.cs程序集相关信息

d.程序集的好处（扩展性）

e.如何添加程序集的引用

  1.添加引用；2.添加命名空间；3.Public关键字

f.反射！！！

  Type类，通过它可以获取类中的所有信息包括方法，属性；可以动态调用类的属性，方法；Type是对类的描述。

  反射就是通过.dll来创建对象，调用成员。

g.步骤

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Reflection;//1.反射命名空间

namespace Reflection
{
    class Program
    {
        static void Main(string[] args)
        {
            //2.加载程序集文件，绝对路径
            string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Common.dll");
            Assembly ass = Assembly.LoadFile(path);

            //3.Assembly类 的方法GetExportedTypes,GetType,GetTypes
            //Type[] types = ass.GetExportedTypes();
            //foreach (Type item in types)
            //{
            //    Console.WriteLine(item.FullName);
            //}
            //Type t = ass.GetType("Common.Person");

            //4.动态创建对象
            //调用了person类中默认无参数的构造函数！
            /*
            object o = ass.CreateInstance("Common.Person");
            Console.WriteLine(o.GetType());
             * */

            //如果类中没有默认无参数的构造函数！
            Type t = ass.GetType("Common.Person");
            object o = Activator.CreateInstance(t, "张三", 18);
            Console.WriteLine(o.GetType());

            PropertyInfo[] pros = o.GetType().GetProperties();
            foreach (PropertyInfo item in pros)
            {
                Console.WriteLine(item.Name);
            }

            //调用Person类中的SayHello
            MethodInfo mdi = o.GetType().GetMethod("SayHello");
            mdi.Invoke(o, null);

            Console.ReadKey();
        }
    }
}

程序集中的相关类：

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

namespace Common
{
    public class Person
    {
        public void Write()
        {
            File.WriteAllText("1.txt", "张三李四王五赵六天气");
        }
        public Person(string name, int age)
        {
            this.Name = name;
            this.Age = age;
        }
        public int Age { get; set; }
        public string Name { get; set; }
        public void SayHello()
        {
            Console.WriteLine("我是Person类中的函数");
        }
    }
}

8.反射常用的函数

代码：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.IO;
using System.Reflection;

namespace Reflection常用函数
{
    class Program
    {
        static void Main(string[] args)
        {
            string path = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "Common.dll");
            Assembly ass = Assembly.LoadFile(path);

            Type t_person = ass.GetType("Common.Person");
            Type t_stu = ass.GetType("Common.Student");
            Type t_tea = ass.GetType("Common.Teacher");

            //Common.Person对象
            object o_person = Activator.CreateInstance(t_person, "xx", 23);
            PropertyInfo pro =o_person.GetType().GetProperty("Age");
            //Console.WriteLine(pro.GetValue(o_person));//获取属性值

            //bool t = t_person.GetType().IsAssignableFrom(t_stu.GetType());
            //bool t = o_person.GetType().IsAssignableFrom(t_person.GetType());//里氏转换,判断是否父类子类

            //bool t = t_tea.GetType().IsInstanceOfType(o_person); //判断指定的对象是否是当前类的实例

            bool t = t_stu.GetType().IsSubclassOf(t_person.GetType());
            //判断当前类是否是指定类的子类

            Console.WriteLine(t);
            Console.ReadKey();

        }
    }
}