public static void Show()
{
Student student = new Student();//声明类以及调用
student.Id = 11;
student.Name = "";
student.Study();
NoReturnWithPara method = new NoReturnWithPara(Plus); //2委托的实例化，传入一个方法名称 要求方法签名一致
NoReturnWithPara method1 = Plus; //简明声明委托
//用Lamdba表达式实现
{
NoReturnWithPara method2 = (x, y) => Console.WriteLine("x={0},y={1}", x, y); //匿名方法体
}
method.Invoke(1, 2); //3调用
method.BeginInvoke(1, 2, null, null); //没有委托就没有异步
method(1, 2); //调用
Plus(4, 5);
method += Plus;
method += Plus;
method += Plus;
method -= Plus;//多播委托
//foreach (NoReturnNoPara item in method.GetInvocationList())//获取委托的实列
//{
// item.Invoke();
//}
}
public void Show()
{
int k = 1;
{
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);
}
{
//anonymous methods
NoReturnNoPara method = new NoReturnNoPara(delegate()
{
Console.WriteLine("this is do nothing in anonymous methods");
});
}
{
//Lambda expression
NoReturnNoPara method = new NoReturnNoPara(() => //"=>" is called goes to.
{
Console.WriteLine("this is do nothing in anonymous methods");
});
}
{
// Lambda expression is not a delegation, or an instance of a delegation. It's a class in another class, a internal method.
NoReturnWithPara method = new NoReturnWithPara((int x, int y) => { });
NoReturnWithPara method1 = new NoReturnWithPara((x, y) => { }); // int could be ignored
NoReturnWithPara method2 = (int x, int y) => { }; //left is decleration, right is a lambda expression
}
}
public void DetegateChangeCode()
{
//1. 1.0 1.1版本时的写法
NoReturnWithPara method1 = new NoReturnWithPara(this.WithParaNothing);
//2.0时的写法
NoReturnWithPara method2 = new NoReturnWithPara(delegate(int x, string s)
{
Console.WriteLine("带参数的方法{0} - {1}", x, s);
});
//3.0时的写法
NoReturnWithPara method3 = new NoReturnWithPara((int x, string s) =>
{
Console.WriteLine("带参数的方法{0} - {1}", x, s);
});
NoReturnWithPara method4 = new NoReturnWithPara((x, s) =>
{
Console.WriteLine("带参数的方法{0} - {1}", x, s);
});
NoReturnWithPara method5 = new NoReturnWithPara((x, s) => Console.WriteLine("带参数的方法{0} - {1}", x, s));
NoReturnWithPara method6 = ((x, s) => {
Console.WriteLine("带参数的方法{0} - {1}", x, s);
Console.WriteLine("111");
});
}
public void Show()
{
int k = 1;
{
//.NET 1.0, 1.1
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);
}
{
// 2.0 匿名方法 访问到调用地方的变量
NoReturnNoPara method = new NoReturnNoPara(delegate()
{
Console.WriteLine("DO Nothing");
Console.WriteLine(k);
});
}
{
// 3.0 lambda 左边是参数列表 goes to 右边是方法体 本质就是一个方法
NoReturnNoPara method = new NoReturnNoPara(() => // goes to
{
Console.WriteLine("DO Nothing");
Console.WriteLine(k);
});
}
{
NoReturnWithPara method = new NoReturnWithPara((int x, int y) =>
{
Console.WriteLine("DO Nothing");
Console.WriteLine(k);
});
}
{
// 可以省略参数类型 自动推算 要么都声明参数类型，要么都不声明
NoReturnWithPara method = new NoReturnWithPara((x, y) =>
{
Console.WriteLine("DO Nothing");
Console.WriteLine(k);
});
}
{
// 方法体只有一行可以省略大括号
NoReturnWithPara method = (x, y) =>
{
Console.WriteLine("DO Nothing");
};
// lambda 表达式是什么？
// 首先不是委托 委托是类型
// 也不是委托的实例
// 只是一个方法 (作用)
// 实际上编译后是一个类中类，里面的一个internal 方法， 然后被绑定到静态委托类型字段
}
}
public void Show()
{
int k = 1;
{
//1.0 1.1
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);
}
{
//2.0 匿名方法
NoReturnNoPara method = new NoReturnNoPara(delegate()
{
Console.WriteLine(k);//能直接用到这里的变量
Console.WriteLine("This is DoNothing1");
});
}
{
//3.0 lambda:左边是参数列表 goes to 右边是方法体 本质就是一个方法
NoReturnNoPara method = new NoReturnNoPara(() =>//goes to
{
Console.WriteLine("This is DoNothing2");
});
}
{
NoReturnWithPara method = new NoReturnWithPara((int x, int y) => { Console.WriteLine("This is DoNothing3"); });
}
{//可以省略掉参数类型 自动推算的
NoReturnWithPara method = new NoReturnWithPara((x, y) => { Console.WriteLine("This is DoNothing4"); });
}
{//方法体只有一行，可以去掉大括号和分号
NoReturnWithPara method = new NoReturnWithPara((x, y) => Console.WriteLine("This is DoNothing5"));
}
{
//可以省略 编译器推算的
NoReturnWithPara method = (x, y) => Console.WriteLine("This is DoNothing6");
}//lambda表达式是个什么呢？
//首先不是委托 委托是类型
//然后也不是委托的实例 因为这里是省略new 委托()
//只是一个方法(作用)
//实际上是一个类中类，里面的一个internal方法，然后被绑定到静态的委托类型字段
{
NoReturnWithPara method = new NoReturnWithPara((x, y) => { Console.WriteLine("This is DoNothing4"); });
method += new NoReturnWithPara((x, y) => { Console.WriteLine("This is DoNothing4"); });
method -= new NoReturnWithPara((x, y) => { Console.WriteLine("This is DoNothing4"); });
method.Invoke(123, 234);//还是执行2遍 lambda的注册是去不掉的
}
{
Action <int> act = i => { };
}
}
public void Show()
{
//2.实例化委托
NoReturnNoPara delegateNoParaObj = new NoReturnNoPara(this.DoNothing);
delegateNoParaObj.Invoke();
NoReturnWithPara delegateWithParaObj = new NoReturnWithPara(this.WithParaNothing);
delegateWithParaObj.Invoke(2, "sss");
for (int i = 0; i < 10; i++)
{
delegateWithParaObj.BeginInvoke(i, i.ToString(), delegate(IAsyncResult t)
{
Console.WriteLine("当前线程ID:" + System.Threading.Thread.CurrentThread.ManagedThreadId);
}, "哈哈哈");
}
}
//2. 委托的使用(在show方法中调用)
public void Show()
{
//以“有参无返回值委托”为例,介绍委托的各种用法
//2.1 用法一
{
NoReturnWithPara methord = new NoReturnWithPara(this.Test1);
methord.Invoke(1, "唐马儒1");
}
//2.2 用法二
{
NoReturnWithPara methord = this.Test1;
methord.Invoke(2, "唐马儒2");
}
//2.3 用法三 DotNet 2.0 时代
{
NoReturnWithPara methord = new NoReturnWithPara
(
delegate(int id, string name)
{
Console.WriteLine("{0} {1}", id, name);
}
);
methord.Invoke(3, "唐马儒3");
}
//2.4 用法四 DotNet 3.0 时代
{
NoReturnWithPara methord = new NoReturnWithPara
(
(int id, string name) =>
{
Console.WriteLine("{0} {1}", id, name);
}
);
methord.Invoke(4, "唐马儒4");
}
//2.5 用法五 委托约束
{
NoReturnWithPara methord = new NoReturnWithPara
(
(id, name) =>
{
Console.WriteLine("{0} {1}", id, name);
}
);
methord.Invoke(5, "唐马儒5");
}
//2.6 用法六 （如果方法体只有一行，可以去掉大括号和分号）
{
NoReturnWithPara methord = new NoReturnWithPara((id, name) => Console.WriteLine("{0} {1}", id, name));
methord.Invoke(6, "唐马儒6");
}
//2.7 用法七
{
NoReturnWithPara methord = (id, name) => Console.WriteLine("{0} {1}", id, name);
methord.Invoke(7, "唐马儒7");
methord(7, "唐马儒7");
}
//2.8 用法八
{
//Func<int, bool> methord = (x) =>
// {
// return x > 6;
// };
//等价于(原理，当只有一个参数的时候，可以省略参数的小括号，当方法体只有一行的时候，可以省略大括号和分号，即lambda形式)
Func <int, bool> methord = x => x > 6;
//等价于 bool methord(int x) => x > 6;
Console.WriteLine(methord(8));
}
}
public void Show()
{
string nameOut = "糯米飞机";
{
Student student = new Student();
student.Id = 1;
student.Name = "打兔子的猎人";
student.Age = 27;
student.ClassId = 2;
student.Study();
}
{
Student student = new Student()
{
Id = 1,
Name = "打兔子的猎人",
Age = 27,
ClassId = 2
};
student.Study();
}
{
NoReturnWithPara method = new NoReturnWithPara(this.DoNothing); //2 委托的实例化
method.Invoke(1, "Gain"); //3 委托的调用
}
{
NoReturnWithPara method = this.DoNothing;
method.Invoke(2, "憨豆");
}
{
NoReturnWithPara method = new NoReturnWithPara(
delegate(int id, string name)
{
Console.WriteLine(nameOut);
Console.WriteLine("{0} {1} DoNothing");
});
method.Invoke(3, "yoyo");
}
{
NoReturnWithPara method = new NoReturnWithPara(
(int id, string name) => //goes to
//lambda表达式：是一个匿名方法，是一个方法
{
Console.WriteLine(nameOut);
Console.WriteLine("{0} {1} DoNothing");
});
method.Invoke(4, "Nine");
}
{
NoReturnWithPara method = new NoReturnWithPara(
(id, name) =>
//去掉参数类型，原因是委托的约束
{
Console.WriteLine("{0} {1} DoNothing");
});
method.Invoke(5, "小昶");
}
{
//如果方法体只有一行，那么可以去掉大括号和分号,多行不行
//如果参数只有一个 可以去掉小括号
//如果没有参数，直接用小括号
NoReturnWithPara method = new NoReturnWithPara((id, name) => Console.WriteLine("{0} {1} DoNothing", id, name));
method.Invoke(6, "梦醒时分");
}
{
NoReturnWithPara method = (id, name) => Console.WriteLine("{0} {1} DoNothing", id, name);
method.Invoke(7, "小石头");
method(8, "Y");
}
{
//0到16个参数 无返回值的委托
Action act1 = () => Console.WriteLine("1234");
Action <int> act2 = t => { };
Action <int, NoReturnWithPara, LambdaShow, LambdaShow, string, string, string, string, string, string, string, string, string, string, string, string> act3 = null;
Action <int, NoReturnWithPara, NoReturnWithPara, LambdaShow, LambdaShow, string, string, string, string, string, string, string, string, string, string, string, string> act4 = null;
}
{
//0到16个参数 带返回值的委托
Func <int> func1 = () => 1;
int i = func1();
Func <int, string> func2 = t => "1234";
Func <int, int, NoReturnWithPara, LambdaShow, LambdaShow, string, string, string, string, string, string, string, string, string, string, string, string> func3 = null;
}
{
//多返回值：1 返回对象 2 ref out
WithReturnWithParaRefOut method = new WithReturnWithParaRefOut(
delegate(ref DateTime time, out int i)
{
i = 1;
return(this);
}); //lambda表达式不行
}
}
public static void Show()
{
NoReturnWithPara method = new NoReturnWithPara(Study);//委托实例化，要求传入的方法必须满足委托的约束
method.Invoke("jack", DateTime.Now);
NoReturnWithPara method1 = new NoReturnWithPara(
delegate(string name, DateTime now) {
Console.WriteLine("{0}{1}正在学习Lambda表达式", name, now);
}); //使用匿名方法，把方法名去掉
method1.Invoke("jack", DateTime.Now);
NoReturnWithPara method2 = new NoReturnWithPara(
(string name, DateTime now) =>
{
Console.WriteLine("{0}{1}正在学习Lambda表达式", name, now);
}); //Lmabda表达式 把delegate换成了=>
method2.Invoke("jack", DateTime.Now);
NoReturnWithPara method3 = new NoReturnWithPara(
(name, now) =>
{
Console.WriteLine("{0}{1}正在学习Lambda表达式", name, now);
}); //去掉了参数类型，委托实例化要求传入的方法必须满足委托的约束
method3.Invoke("jack", DateTime.Now);
NoReturnWithPara method4 = (name, now) =>
{
Console.WriteLine("{0}{1}正在学习Lambda表达式", name, now);
}; //去掉了new NoReturnWithPara();
method4.Invoke("jack", DateTime.Now);
NoReturnWithPara method5 = (name, now) => Console.WriteLine("{0}{1}正在学习Lambda表达式", name, now);
//去掉了{},条件是方法体只有一行;
method5.Invoke("jack", DateTime.Now);
NoReturnWithPara method10 = (s, b) => Console.WriteLine("{0}{1}正在学习Lambda表达式", s, b);
method10.Invoke("jack", DateTime.Now);
Console.WriteLine("===============================================");
WithReturnWithoPara func = (x, y) => { return(x * y); };
WithReturnWithoPara func1 = (x, y) => x * y;//去掉了{},条件是方法体只有一行,带返回值的话，return就去掉;
func.Invoke(3, 4);
func1.Invoke(3, 4);
Console.WriteLine("===============================================");
NoReturnNoPara action = () => { };
NoReturnNoPara action1 = () => { Console.WriteLine("12345"); };
Console.WriteLine("===============================================");
WithReturnNoPara fun = () => "erfdfa";
Console.WriteLine("===============================================");
//系统自带的各种委托
#region 带返回值的委托
Action act1 = () => { };
//泛型委托
Action <string> act2 = name => { Console.WriteLine(); };//一个参数的话，可以去掉小括号
//最多可以有16个参数
Action <string, int, long, DateTime, char, double, decimal> act3 = (par1, par2, par3, par4, par5, par6, par7) => { };
#endregion
#region 带返回值的委托
Func <string> fun1 = () => "fdafds";
Func <DateTime> fun2 = () => DateTime.Now;
//最多可以有16个参数,带一个返回值
Func <string, int, long, DateTime, char, double, decimal, DateTime> fun3 = (par1, par2, par3, par4, par5, par6, par7) => DateTime.Now;
Func <string, int, long, DateTime, char, double, decimal, Action> fun4 = (par1, par2, par3, par4, par5, par6, par7) => act1;
#endregion
}
public void Show()
{
{
NoReturnWithPara func = (x, y) => { };
func += (x, y) => Console.WriteLine("123");;
func.Invoke(3, 4);
}
//System.MulticastDelegate
Student student = new Student()
{
Id = 96,
Name = "Summer"
};
student.Study();
//Predicate<int>
//Func<string>
{
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);//2 委托的实例化
method.Invoke();//3 委托的调用
method();
//method.BeginInvoke(null, null);
this.DoNothing();
}
{
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing); //当前类的实例方法
NoReturnNoPara method1 = new NoReturnNoPara(MyDelegate.DoNothingStatic); //当前类的静态方法
NoReturnNoPara method2 = new NoReturnNoPara(student.Study); //其他类的实例方法
NoReturnNoPara method3 = new NoReturnNoPara(Student.StudyAdvanced); //其他类的静态方法
}
{
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);
method += new NoReturnNoPara(this.DoNothing);
method += new NoReturnNoPara(MyDelegate.DoNothingStatic);
method += new NoReturnNoPara(student.Study);
method += new NoReturnNoPara(Student.StudyAdvanced);
method += new NoReturnNoPara(new Student().Study);
method += new NoReturnNoPara(Student.StudyAdvanced);
method += new NoReturnNoPara(() => Console.WriteLine("这里是lambda表达式"));
//+=就是把多个方法按顺序排成列表，invoke时按顺序执行
//method.Invoke();
method -= new NoReturnNoPara(this.DoNothing);
method -= new NoReturnNoPara(MyDelegate.DoNothingStatic);
method -= new NoReturnNoPara(student.Study);
method -= new NoReturnNoPara(new Student().Study);
method -= new NoReturnNoPara(Student.StudyAdvanced);
method -= new NoReturnNoPara(Student.StudyAdvanced);
method -= new NoReturnNoPara(() => Console.WriteLine("这里是lambda表达式"));
//-=就是从这个实例上，从后往前挨个匹配，找到第一个完全吻合的移除掉，且只移除一个，找不到不异常
method.Invoke();
//method.BeginInvoke(null, null);
foreach (NoReturnNoPara item in method.GetInvocationList())
{
item.BeginInvoke(null, null);
}
}
}
public void Show()
{
{
//1.0最普通的写法
NoReturnWithPara mathod = new NoReturnWithPara(this.TestFunction); //实例化委托
mathod.Invoke(123, "hzq"); //委托实例的调用
}
{
//2.0方法，匿名方法
NoReturnWithPara mathod = new NoReturnWithPara(
delegate(int id, string name)
{
Console.WriteLine($"ID：{id}，Name:{name}");
}
);
mathod.Invoke(123, "hzq");
}
{
//3.0 Lambda表达式
NoReturnWithPara mathod = new NoReturnWithPara(
(int id, string name) => //gose to Lambda表达式，左边是参数列表右边是方法体
{
Console.WriteLine($"ID：{id}，Name:{name}");
}
);
mathod.Invoke(123, "hzq");
}
{
//Lambda表达式的语法糖，省略类型
NoReturnWithPara mathod = new NoReturnWithPara(
(id, name) =>
{ //编译器语法糖
Console.WriteLine($"ID:{id},Name:{name}");
}
);
mathod.Invoke(333, "cc");
}
{
//Lambda表达式的进一步缩减
NoReturnWithPara mathod = (id, name) => Console.WriteLine($"ID:{id},Nmae:{name}");
mathod.Invoke(30789, "hzq");
}
//.Net3.0系统自带的委托，Action,Func
Console.WriteLine();
Console.WriteLine();
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Lambda表达式（系统自带委托，无参数无返回值）");
{
//1.0
Action act = new Action(this.TestNoParaFuntion);
act.Invoke();
}
{
//2.0
Action act = new Action(
delegate()
{
this.TestNoParaFuntion();
}
);
act.Invoke();
}
{
Action act = new Action(
() => this.TestNoParaFuntion()
);
act.Invoke();
}
{
Action act = () => this.TestNoParaFuntion();
act.Invoke();
}
Console.WriteLine();
Console.WriteLine();
Console.WriteLine();
Console.WriteLine();
Console.WriteLine("Lambda表达式（系统自带委托，有参数无返回值）");
{
//2.0匿名函数
Action <int, string> act = new Action <int, string>( //泛型委托
delegate(int id, string name) {
Console.WriteLine($"ID:{id},Name:{name}");
}
);
act.Invoke(6666, "HZQ");
}
{
//3.0写法，lambda表达式
Action <int, string> act = (id, name) => Console.WriteLine($"ID：{id},Nmae:{name}");
act.Invoke(567, "HZQ");
}
}
public void Show()
{
Console.WriteLine("lambda演变历史");
{
Console.WriteLine(".NetFramework1.0 1.1");
Console.WriteLine("执行无参无返回值委托");
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);
method.Invoke();
}
{
Console.WriteLine("执行有参无返回值委托");
NoReturnWithPara method = new NoReturnWithPara(this.Study);
method.Invoke(20200316, "2020年3月16日17:56:21");
}
{
Console.WriteLine(".NetFramework2.0 匿名方法，delegate关键字");
//可以访问局部变量
NoReturnWithPara method = new NoReturnWithPara(delegate(int id, string name)
{
Console.WriteLine($"***这是方法***：匿名方法：{id} {name}");
});
method.Invoke(20200316, "2020年3月16日17:02:23");
}
{
Console.WriteLine(".NetFramework3.0 把delegate关键字去掉，增加了一个箭头goes to 也就是：=>");
NoReturnWithPara method = new NoReturnWithPara(
(int id, string name) =>
{
Console.WriteLine($"***这是方法***：{id} {name}");
});
method.Invoke(20200316, "2020年3月16日17:06:31");
Console.WriteLine("Action方法");
Action <string, string> actionA = (string str1, string str2) =>
{
Console.WriteLine($"***这是方法***：参数1：{str1}，参数2：{str2}");
};
actionA.Invoke("ABC", "CBA");
}
{
Console.WriteLine("//省略参数类型，编译器的语法糖，虽然没写，编译时还是有的，根据委托推算");
NoReturnWithPara method = new NoReturnWithPara(
(id, name) =>
{
Console.WriteLine($"{id} {name}");
});
method.Invoke(20200316, "2020年3月16日17:13:11");
Console.WriteLine("Action方法");
Action <int, string> actionB = (int1, str1) =>
{
Console.WriteLine($"***这是方法***：参数1{str1}，参数2：{str1}");
};
actionB.Invoke(20200316, "2020年3月16日17:20:03");
}
{
Console.WriteLine("如果方法体只有一行，可以去掉大括号和分号");
NoReturnWithPara method = new NoReturnWithPara(
(id, name) => Console.WriteLine($"{id} {name}"));
method.Invoke(20200316, "2020年3月16日17:22:59");
}
{
Console.WriteLine("new NoReturnWithPara可以省掉，也是语法糖，编译器自动加上");
NoReturnWithPara method = (id, name) => Console.WriteLine($"{id} {name}");
method.Invoke(123, "大涛");
}
Console.WriteLine("lambda表达是什么？ lambda只是实力化委托的一个参数，就是个方法");
Console.WriteLine("lambda是匿名方法，但是编译的时候会分配一个名字,还会产生一个私有sealed类，这里增加一个方法");
{
Console.WriteLine("lambda在多播委托");
NoReturnWithPara method = new NoReturnWithPara(this.Study);
method += this.Study;
method += (id, name) => Console.WriteLine($"{id} {name}");
method -= this.Study;
method -= (id, name) => Console.WriteLine($"{id} {name}");
Console.WriteLine("多播委托里面的lambda无法移除， 不是2个实例，其实是2个不同的方法,因为在编译的时候，会生成两个方法名不同的方法");
method.Invoke(20200316, "2020年3月16日17:26:12");
}
{
Console.WriteLine("==========有返回值，有参数==========");
Func <int, int, int> funcA = (a, b) =>
{
return(a + b);
};
Console.WriteLine("如果方法体只有一行也可以省略大括号");
Func <int, int, int> funcB = (a, b) => a + b;
int c = funcA.Invoke(12, 13);
int d = funcB.Invoke(10, 30);
Console.WriteLine($"FuncA返回值：{c}");
Console.WriteLine($"FuncB返回值：{d}");
}
}
public void Show()
{
//lambda演变历史
{
//.NetFramework1.0 1.1
NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);
}
int i = 10;
{
NoReturnWithPara method = new NoReturnWithPara(this.Study);
method.Invoke(123, "董小姐");
}
{
//.NetFramework2.0 匿名方法，delegate关键字
//可以访问局部变量
NoReturnWithPara method = new NoReturnWithPara(delegate(int id, string name)
{
Console.WriteLine(i);
Console.WriteLine($"{id} {name} 学习.Net高级班");
});
method.Invoke(234, "Harley");
}
{
//.NetFramework3.0 把delegate关键字去掉，增加了一个箭头goes to
//lambda表达式 参数列表=>方法体
NoReturnWithPara method = new NoReturnWithPara(
(int id, string name) =>
{
Console.WriteLine($"{id} {name} 学习.Net高级班");
});
method.Invoke(123, "Coder");
}
{
NoReturnWithPara method = new NoReturnWithPara(
(id, name) =>//省略参数类型，编译器的语法糖，虽然没写，编译时还是有的，根据委托推算
{
Console.WriteLine($"{id} {name} 学习.Net高级班");
});
method.Invoke(123, "加菲猫");
}
{
NoReturnWithPara method = new NoReturnWithPara(
(id, name) => Console.WriteLine($"{id} {name} 学习.Net高级班"));
//如果方法体只有一行，可以去掉大括号和分号
method.Invoke(123, "ZJ");
}
{
NoReturnWithPara method = (id, name) => Console.WriteLine($"{id} {name} 学习.Net高级班");
method.Invoke(123, "大涛"); //new NoReturnWithPara可以省掉，也是语法糖，编译器自动加上
}
//lambda表达是什么？ lambda只是实力化委托的一个参数，就是个方法
//lambda是匿名方法，但是编译的时候会分配一个名字
//还会产生一个私有sealed类，这里增加一个方法
{
//lambda在多播委托
NoReturnWithPara method = new NoReturnWithPara(this.Study);
method += this.Study;
method += (id, name) => Console.WriteLine($"{id} {name} 学习.Net高级班1");
method -= this.Study;
method -= (id, name) => Console.WriteLine($"{id} {name} 学习.Net高级班1");
//多播委托里面的lambda无法移除， 不是2个实例，其实是2个不同的方法
method.Invoke(345, "北纬23");
}
{
//匿名方法或者lamdba表达式是不是只能是无返回值的
Action action0 = () => { };
Action <string> action1 = s => Console.WriteLine(s); //参数只有一个 可以省略小括号
Func <int> func0 = () => DateTime.Now.Month; //如果方法体只有一行，去掉大括号分号return
int iResult = func0.Invoke();
}
}
