C#泛型约束与调用

1、C#泛型

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;using System.Data;using System.Data.SqlClient;namespace ConsoleApplication1{    class Program    {        static void Main(string[] args)        {            Student<string> stu = new Student<string>();            stu.Age = 12;            stu.Name = "Luck";            string name = "小王";            Console.WriteLine(stu.Info(name));            //泛型类约束结构约束,T必须是值类型            StudentStruct<structA> stustru = new StudentStruct<structA>();            structA s;            s.age = 24;            Console.WriteLine(stustru.Ages(s.age));            //泛型类约束类约束,T必须是引用类型(这里用string)            StudentClass<string> stuClass = new StudentClass<string>();            name = "王力宏";            stuClass.className = "哥伦比亚大学";            Console.WriteLine(stuClass.Study(name));            Console.WriteLine("王力宏毕业于：{0}，{1}；", stuClass.className, stuClass.Study(name));            //泛型类约束类约束,T必须是引用类型(这里用类类型)            StudentClass2<StudentsInfo> stuInfoClass = new StudentClass2<StudentsInfo>(); StudentsInfo sclaa = new StudentsInfo();            stuInfoClass.Study(sclaa);            //泛型类约束接口约束,T必须是实现接口            StudentInterface<IStudents> stuInter = new StudentInterface<IStudents>();            int id = 5;            DataTable dt = stuInter.dataInfo(id);            Console.WriteLine("{0}     {1}\r\n", "ID", "Name");            foreach (DataRow dr in dt.Rows)            {                Console.WriteLine("{0}     {1}\r\n", dr["ID"].ToString(), dr["Name"].ToString());            }            //泛型类约束,T必须是派生自基类            StudentObj<StudentsSubclass> stuobj = new StudentObj<StudentsSubclass>();            StudentsSubclass sub = new StudentsSubclass();            stuobj.Studys(sub);            //泛型类约束,构造函数约束(T必须有一个默认的构造函数)            StudentNew<StudentConstructor> snews = new StudentNew<StudentConstructor>();            StudentConstructor scon = new StudentConstructor();            snews.Studys(scon);            //泛型类约束,这里T派生自泛型类型K,该类型称为裸类型约束            StudentT<StudentK<StudentsInfo>> sTK = new StudentT<StudentK<StudentsInfo>>();            StudentK<StudentsInfo> sks = new StudentK<StudentsInfo>();            name = "$C#语法";            sTK.Studys(name);        }    }    //基本类型    public class StudentsInfo    {        public string Name { get; set; }        public void Speak(StudentsInfo intos)        {            intos.Name = "温家波";            Console.WriteLine(Name + "/习近平召开十九大会议");        }    }    //泛型类    public class Student<T>    {        public int Age { get; set; }        public string Name { get; set; }        public string Info(T name)        {            return name + "是三好学生";        }    }    //泛型类约束结构约束,T必须是值类型    //byte，short，int，long，float，double，decimal，char，bool 和 struct 统称为值类型。    //string 和 class统称为引用类型。    //引用类型：基类为Objcet    //值类型：均隐式派生自System.ValueType：    public class StudentStruct<T> where T : struct    {        public string Infos(T name)        {            return name + "在学习";        }        public string Ages(int age)        {            return "李四的年龄是：" + age;        }    }    //结构    //这里注意C#结构与类的区别    public struct structA    {        //public int A = 90; //错误:“structA.A”: 结构中不能有实例字段初始值        public int age;        public structA(int n)        {            this.age = n;        }    }    //泛型类约束类约束,T必须是引用类型    public class StudentClass<T> where T : class    {        public string className { get; set; }        public string Study(T name)        {            return name + "在学习声乐";        }    }    public class StudentClass2<T> where T : class    {        public void Study(T name)        {            StudentsInfo stu = new StudentsInfo();            stu.Name = "张德江";            stu.Speak(stu);        }    }    //泛型类约束接口约束,T必须是实现接口    public class StudentInterface<T> where T : IStudents    {        public DataTable dataInfo(int id)        {            //DataTable创建行和列http://www.cnblogs.com/jRoger/articles/1887581.html            DataTable dt = new DataTable();            DataColumn dc = null;            dc = dt.Columns.Add("ID", Type.GetType("System.Int32"));            dc.AutoIncrement = true;//自动增加             dc.AutoIncrementSeed = 1;//起始为1             dc.AutoIncrementStep = 1;//步长为1             dc.AllowDBNull = false;            dc = dt.Columns.Add("Age", typeof(string));            dc = dt.Columns.Add("Name", Type.GetType("System.String"));            DataRow newRow;            newRow = dt.NewRow();            newRow["Age"] = "23";            newRow["Name"] = "湖北";            dt.Rows.Add(newRow);            newRow = dt.NewRow();            newRow["Age"] = "19";            newRow["Name"] = "五五";            dt.Rows.Add(newRow);            return dt;        }    }    //接口    public interface IStudents    {        DataTable dataInfo(int id);    }    //泛型类约束,T必须是派生自基类    public class StudentObj<T> where T : StudentsSubclass    {        public void Studys(T name)        {            StudentsSubclass s = new StudentsSubclass();            s.Name = "Net";            s.Study(s.Name);        }    }    //C#子类    public class StudentsSubclass : StudentsInfo    {        public void Study(string name)        {            Console.WriteLine(name + "复习C#");        }    }    //泛型类约束,构造函数约束(T必须有一个默认的构造函数)    public class StudentNew<T> where T : new()    {        public void Studys(T name)        {            StudentConstructor s = new StudentConstructor();            string Name = "new()";            s.Study(Name);        }    }    public class StudentConstructor    {        public StudentConstructor()        { }        public void Study(string name)        {            Console.WriteLine(name + "复习C#");        }    }    // 泛型类约束,这里T派生自泛型类型K,该类型称为裸类型约束    public class StudentT<T> where T : StudentK<StudentsInfo>    {        StudentK<StudentsInfo> skinfo = new StudentK<StudentsInfo>();        public void Studys(string name)        {            string Name = "&TK泛型";            skinfo.Study(Name);        }    }    public class StudentK<K> where K : class    {        public void Study(string name)        {            Console.WriteLine(name + "会议进行中");        }    }}