Question

C# List<>中遍历不同类型的数据？？？

List<Person> person = new List<Person>();
Person p1 = new Person("张三", 26, Gender.Male, "看书");
Person p2 = new Person("张四", 55, Gender.Male, "钓鱼");

List<Student> stu = new List<Student>();
Student s1 = new Student("李四", 26, Gender.Male, "电影", "S2T11");
Student s2 = new Student("李五", 20, Gender.Male, "电脑", "S2T11");

List<Teacher> tch = new List<Teacher>();
Teacher t1 = new Teacher("王五", 26, Gender.Male, "音乐", "S1,S2,Y2");
Teacher t2 = new Teacher("王六", 30, Gender.Male, "音乐", "S1,S2");

person.Add(p1);
person.Add(p2);
person.Add(s1);
person.Add(s2);
person.Add(t1);
person.Add(t2);
/////////////用for遍历出Student类型和Teacher类型///////////////////
for (int i = 0; i < person.Count; i++)
{
if (person[i] is Student)
{
((Student)person[i]).SayHi();
}
else if (person[i] is Teacher)
{
((Teacher)person[i]).SayHi();
}
}
//////////////////////////////
怎么用foreach来遍历出Student类型和Teacher类型
替换上面for的遍历
可以通过编译 而且用for可以遍历出Student类型和Teacher类型
我已经运行过了
现在想用foreach来替换 但是写了写foreach这里报错 不晓得怎么写了
基类 Person 子类 Student Teacher

Answer 1

Person, Student, Teacher这三个类都做一个基类PersonBase
然后再：
List<PersonBase> personBaseList = new List<PersonBase>();

PersonBase p1 = new Person("张三", 26, Gender.Male, "看书");
PersonBase p2 = new Person("张四", 55, Gender.Male, "钓鱼");

PersonBase s1 = new Student("李四", 26, Gender.Male, "电影", "S2T11");
PersonBase s2 = new Student("李五", 20, Gender.Male, "电脑", "S2T11");

PersonBase t1 = new Teacher("王五", 26, Gender.Male, "音乐", "S1,S2,Y2");
PersonBase t2 = new Teacher("王六", 30, Gender.Male, "音乐", "S1,S2");

personBaseList.Add(p1);
personBaseList.Add(p2);
personBaseList.Add(s1);
personBaseList.Add(s2);
personBaseList.Add(t1);
personBaseList.Add(t2);

foreach(PersonBase p in personBaseList)
{
if(p is Student){....}
.......................
}

Answer 2

foreach(Person per in person)
{
//可以打印出Person类中的per对象中的属性或者方法
}
foreach(Student st in stu)
{
//可以打印出Student类中的st对象中的属性或者方法
}
foreach(Teacher tc in tch)
{
//可以打印出Teacher类中的tc对象中的属性或者方法
}

List<> 这里面是约束类型的泛型。

Answer 3

C语言_023_输出显示不同类型数据_上

Answer 4

这段代码只怕是不能通过编译.
person使用了范性,该对象只能保存Person类型的,而你在后面又add了 Student ,Teacher 两个类型的对象.