C#泛型集合类System.Collections.Generic

void Main()
{
    //实例化泛型类时，才指定具体的类型
    MyGenericClass<int> MyGeneri = new MyGenericClass<int>(5);
    Console.WriteLine(MyGeneri.InnerT1Object * 2);
}

public class MyGenericClass<T>//<T1,T2,T3>表示多个类型参数
{
    private T innerT1Object;
    public string LastName;
public MyGenericClass(T item)//构造函数
    {
        this.innerT1Object = item;
    }
public T InnerT1Object//泛型属性
    {
        get { return innerT1Object; }
    }
}

public class MyGenericClass<T> where T : new()
{
    private T innerT1Object = new T();
}

public bool Compare(T op1, T op2)
{
    if (op1 != null && op2 == null)//正确。如果T为值类型，op1!=null始终成立。
    {
        //…
    }
    if (op1 == op2)//错误，因为这就假定了T支持==运算符
    {
        //…
    }
}

public class MyGenericClass<T>
{
    private T innerT1Object = default(T);
}

class MyGenericClass<T> where T:Animal

void Main()
{
    StaticDemo<string>.x=4;
    StaticDemo<int>.x=5;
}

public class StaticDemo<T>  
{
    public  static int x;
}

public class Farm<T> where T : Animal
{
    //...
}

public class SuperFarm<T> : Farm<T> where T : SuperCow //SuperCow为Animal的子集
{
    //...
}

public class Cards : List<Card> //派生非泛型
{ }

public static Farm<T> operator +(Farm<T> farm1, Farm<T> farm2)
{ }

public struct MyStruct<T1, T2>
{
    public T1 item1;
    public T2 item2;
}

interface myInterface<T> where T : Animal
{
    bool Brea(T animal1, T animal2);
    T oldest { get; }
}

public interface IComparable<T>
{
    int CompareTo(T other);
}

public class Person : IComparable<Person>
{
    public int CompareTo(Person other)
    {
        return this.name.CompareTO(other.name);
    }
}

public class Defaulter
{
    public T GetDefault<T>()
    {
        return default(T);
    }
}

public class Defaulter<T1>
{
    public T2 GetDefault<T2>() where T2 : T1 //泛型方法的参数最好不要与其所在的泛型类的类型参数相同
    {
        return default(T2);
    }

    public void Process()
    {
    }
    public void Process<T>(T1 op1)//重载方法1
    {
    }

    public void Process<T, U>(T1 op1)//重载方法2
    {
    }
}

public delegate T1 MyDelegate<T1, T2>(T2 op1, T2 op2) where T1 : T2;

Action action1 = () => Console.Write("a");
action1();

Action<string> action2 = (p) => Console.Write(p);
action2("b");

private void button1_Click(object sender, EventArgs e)
{
    WaitCallback waitCallBack = new WaitCallback(this.AlternationUsingAction);
    ThreadPool.QueueUserWorkItem(waitCallBack, "Action的使用");
}

private void AlternationUsingAction(object text)
{
    this.Invoke((Action)( () =>
      {
          button1.Text = text.ToString();
      } ));
}

Func<int, int, string > Func = (a, b) => (a + b).ToString();
Console.Write(Func(1, 2));

public delegate bool Predicate<T>(T obj);//判断条件函数
public T Find(Predicate<T> matach);

Predicate<string[]> predicate = x =>
                   {
                       var result = from p in x
                                    where p.Contains("s")
                                    select p;
                       return result.ToList().Count > 0;

                   };
string[] _value = { "charlies", "nancy", "alex", "jimmy", "selina" };
Console.WriteLine(predicate(_value) ? "包含." : "不包含");

public delegate int Comparision<T>(T obj1,T obj2)//
public void Sort(Comparision<T> comprison)

public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e) where TEventArgs : EventArgs;

public delegate TSummary Action<TInput, TSummary>(TInput t, TSummary u);//定义泛型委托
public static TSummary Accumulate<TInput, TSummary>(IEnumerable <TInput> cols, Action<TInput, TSummary> action)
//将委托实例action传给方法参数。
{
    TSummary sum = default(TSummary);
    foreach (TInput input in cols)
    {
        sum = action(input, sum);//执行委托方法
    }
    return sum;
}

void Main()
{
    decimal amount = Accumulate<int, decimal>(new List<int> { 1, 2 }, (a, b) => a + b);//(a, b) => a + b为委托实例
    Console.Write(amount);
}

//定义了一个泛型委托，该委托指定了发送者的具体类型
public delegate void MyEventHandler<T>(Publisher<T> Sender);

void Main()
{
    //事件发布者
    Publisher<int> publisherI = new Publisher<int>();
    Publisher<double> publisherD = new Publisher<double>();

    //事件订阅者
    Receiver receiver = new Receiver();

    //开始绑定事件
    publisherI.Click += receiver.OnClick;
    publisherD.Click += receiver.OnClick;

    //引发事件
    publisherI.SendMessage();
    publisherD.SendMessage();
}

//消息发布者类Publisher<T>的代码
public class Publisher<T>
{
    //定义了一个泛型事件，该事件的发布者的类型是强类型
    public event MyEventHandler<T> Click;

    //发送事件函数
    public void SendMessage()
    {
        Click(this);
    }
}

//消息订阅者类Receiver的代码
class Receiver
{
    //事件处理函数，该函数具有强类型的参数表示发送者
    public void OnClick(Publisher<int> sender)
    {
        Console.WriteLine("该事件已经写入日志文件");
    }

    //事件处理函数
    public void OnClick(Publisher<double> sender)
    {
        Console.WriteLine("该事件已经发送到主管信箱");
    }
}

Nullable<int> x = 4;//可写成int? x = 4
x = null;//可为可空类型赋值null.

int y;
if (x.HasValue)//或者x!=null
{
    y = x = value;
}
else
{
    y = x ?? 0;//或者    x.GetValueOrDefault(); x=null则或者其默认值。
}

int? op1=5;
int? result=op1 *2;

int? op2=5;
int result1=op2 *2;//如果op2为null，强制转换int?到int产生异常

int[] arr = { 1, 2, 3, 4, 5, 6, 7, 8 };
ArraySegment<int> segment = new ArraySegment<int>(arr, 2, 3);
for (int i = segment.Offset; i < segment.Offset + segment.Count; i++)
{
    Console.WriteLine(segment.Array[i]);
}