泛型约束where条件的使用（可以通过类型参数动态反射创建实例）

定义抽象的人类

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

namespace ConsoleApplication1

{   public  abstract class  person

{

public abstract  string ting();    public abstract  string shuo();

}

}

定义子类 girl 和boy 类

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

namespace ConsoleApplication1 {

public class girl : person

{

public override string ting()         {             return "girl ting";         }

public override string shuo()         {             return "girl shuo";         }

}

}

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

namespace ConsoleApplication1 {

public class boy: person

{

public override string ting()         {             return "boy ting";         }

public override string shuo()         {             return "boy shuo";         }

}

}

定义模具类可以 可以返回一个boy或者girl的实例

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

namespace ConsoleApplication1 {

public  class zhongjian     {

public static person CreatePerson<T>() where T:person

{

person  p = Activator.CreateInstance(typeof(T)) as person;         return p;

}

}

}

模拟环境类 program

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

namespace ConsoleApplication1

{

class Program

{

static void Main(string[] args)

{       person p= zhongjian.CreatePerson<girl>();            string shuo= p.shuo();            string ting=  p.ting();            Console.WriteLine(shuo+"\t"+ting);

Console.ReadKey();

}

}

}