04.C#委托、Lambda表达式

delegate string DelegateMethod(int a, int b);//定义委托
class Program
{
    static void Main(string[] args)
    {
        DelegateMethod dm = new DelegateMethod(Method);//或：DelegateMethod dm = Method
        Console.WriteLine(dm(10, 20));//执行委托
        Console.Read();
    }
    private static string Method(int a, int b)
    {
        return "相加结果：" + (a + b);
    }
}

delegate string DelegateMethod(int a, int b);//定义委托
class Program
{
    static void Main(string[] args)
    {
        DelegateMethod dm = Method;
        Console.WriteLine(dm.Invoke(10, 20));//执行委托
        Console.Read();
    }
    private static string Method(int a, int b)
    {
        return "相加结果：" + (a + b);
    }
}

delegate void DelegateMethod(int a, int b);//定义委托
class Program
{
    static void Main(string[] args)
    {
        DelegateMethod dm = Method;
        for (int i = 0; i < 10; i++)
        {
            dm.BeginInvoke(i, 20, null, null);//异步调用委托
        }
        Console.Read();
    }
    private static void Method(int a, int b)
    {
        Console.WriteLine("相加结果：" + (a + b));//执行委托
    }
}

delegate void DelegateMethod(int a, int b);//定义委托
class Program
{
    static void Main(string[] args)
    {
        DelegateMethod dm = Method;
        dm.BeginInvoke(10, 20, MethodCompleted, null);//异步调用委托
        Console.Read();
    }
    //异步委托
    private static void Method(int a, int b)
    {
        Console.WriteLine("相加结果：" + (a + b));
        Thread.Sleep(3000);
    }
    //回调函数
    private static void MethodCompleted(IAsyncResult ar)
    {
        Console.WriteLine("休眠结束！");
    }
}

delegate string DelegateMethod(int a, int b);//定义委托
class Program
{
    static void Main(string[] args)
    {
        DelegateMethod dm = Method;
        IAsyncResult ar = dm.BeginInvoke(10, 20, null, null);//异步调用委托
        string result = dm.EndInvoke(ar);//等待委托异步调用结束
        Console.WriteLine(result);//输出返回值
        Console.Read();
    }
    //异步委托
    private static string Method(int a, int b)
    {
        Thread.Sleep(3000);
        return "相加结果：" + (a + b);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Action<int,int> dm = Method;//委托实例
        dm(10,20);//调用委托
        Console.Read();
    }
    private static void Method(int a, int b)
    {
        Console.WriteLine("相加结果：" + (a + b));
    }
}

class Program
{
    static void Main(string[] args)
    {
        Func<int, int, string> dm = Method;//委托实例
        string result = dm(10, 20);//调用委托
        Console.WriteLine(result);//输出返回值
        Console.Read();
    }
    private static string Method(int a, int b)
    {
        return "相加结果：" + (a + b);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Predicate<int> dm = Method;//委托实例
        if (dm(12))//调用委托
        {
            Console.WriteLine("偶数");
        }
        else
        {
            Console.WriteLine("奇数");
        }
        Console.Read();
    }
    private static bool Method(int a)
    {
        if(a%2==0)
        {
            return true;
        }
        return false;
    }
}

class Program
{
    static void Main(string[] args)
    {
        Action<int> dm = null; //委托实例
        for (int i = 0; i < 20; i++)
        {
            if (i % 2 == 0)
            {
                dm += Method1;
            }
            else
            {
                dm += Method2;
            }
        }
        dm(123456);//调用多播委托
        Console.Read();
    }
    private static void Method1(int a)
    {
        Console.WriteLine("委托1：" + a);
    }
    private static void Method2(int a)
    {
        Console.WriteLine("委托2：" + a);
    }
}

class Program
{
    static void Main(string[] args)
    {
        Action<int> dm = delegate(int a)
        {
            Console.WriteLine(a.ToString());
        };//匿名方法
        dm(123456);//调用委托指向的匿名方法
        Console.Read();
    }
}

class Program
{
    static void Main(string[] args)
    {
        //标准的Lambda格式
        Func<int, int, string> sum0 = (int a, int b) => { return "和是：" + (a + b); };
        Console.WriteLine(sum0(10, 20));
        //简写格式
        Func<int, int, string> sum1 = (a, b) => "和是：" + (a + b);
        Console.WriteLine(sum1(30, 40));
        Action<int, int> sum2 = (a, b) => Console.WriteLine("和是：" + (a + b));
        sum2(50, 60);
        Console.Read();
    }
}

Action<int, int> sum = (a, b) => { int i = a = +b; Console.Write(i); };

Action<int, int> sum = (a, b) => Console.Write(a + b);

Func<int, int, string> sum0 = (a, b) => { return "和是：" + (a + b); };

Func<int, int, string> sum1 = (a, b) => "和是：" + (a + b);

List<int> list = new List<int>(); 
list.RemoveAll(i => i < 100);//i会被猜测为int