教 程 目 录
属性是类,结构和接口的命名成员.一个或多个类中的成员变量或方法称为 Fields .属性是字段的扩展,可以使用相同的语法进行访问.他们使用访问者,通过它们可以读取,写入或操纵私有字段的值.
属性不命名存储位置.相反,他们有访问者来读取,写入或计算他们的值.
例如,让我们有一个名为Student的类,其中包含年龄的私有字段,名称和代码.我们无法直接从类范围外访问这些字段,但我们可以拥有访问这些私有字段的属性.
访问者
属性的存取器包含有助于获取(读取或计算)或设置(写入)属性的可执行语句.访问器声明可以包含get访问器,set访问器或两者.例如 :
// Declare a Code property of type string:
public string Code {
get {
return code;
}
set {
code = value;
}
}
// Declare a Name property of type string:
public string Name {
get {
return name;
}
set {
name = value;
}
}
// Declare a Age property of type int:
public int Age {
get {
return age;
}
set {
age = value;
}
}
示例
以下示例演示如何使用属性 :
using System;
namespace IT屋 {
class Student {
private string code = "N.A";
private string name = "not known";
private int age = 0;
// Declare a Code property of type string:
public string Code {
get {
return code;
}
set {
code = value;
}
}
// Declare a Name property of type string:
public string Name {
get {
return name;
}
set {
name = value;
}
}
// Declare a Age property of type int:
public int Age {
get {
return age;
}
set {
age = value;
}
}
public override string ToString() {
return "Code = " + Code +", Name = " + Name + ", Age = " + Age;
}
}
class ExampleDemo {
public static void Main() {
// Create a new Student object:
Student s = new Student();
// Setting code, name and the age of the student
s.Code = "001";
s.Name = "Zara";
s.Age = 9;
Console.WriteLine("Student Info: {0}", s);
//let us increase age
s.Age += 1;
Console.WriteLine("Student Info: {0}", s);
Console.ReadKey();
}
}
}
编译并执行上述代码时,会产生以下结果 :
Student Info: Code = 001, Name = Zara, Age = 9
Student Info: Code = 001, Name = Zara, Age = 10
抽象属性
抽象类可能有一个抽象属性,应该在派生类中实现.以下程序说明了这个 :
using System;
namespace IT屋 {
public abstract class Person {
public abstract string Name {
get;
set;
}
public abstract int Age {
get;
set;
}
}
class Student : Person {
private string code = "N.A";
private string name = "N.A";
private int age = 0;
// Declare a Code property of type string:
public string Code {
get {
return code;
}
set {
code = value;
}
}
// Declare a Name property of type string:
public override string Name {
get {
return name;
}
set {
name = value;
}
}
// Declare a Age property of type int:
public override int Age {
get {
return age;
}
set {
age = value;
}
}
public override string ToString() {
return "Code = " + Code +", Name = " + Name + ", Age = " + Age;
}
}
class ExampleDemo {
public static void Main() {
// Create a new Student object:
Student s = new Student();
// Setting code, name and the age of the student
s.Code = "001";
s.Name = "Zara";
s.Age = 9;
Console.WriteLine("Student Info:- {0}", s);
//let us increase age
s.Age += 1;
Console.WriteLine("Student Info:- {0}", s);
Console.ReadKey();
}
}
}
编译并执行上述代码时,会产生以下结果 :
Student Info: Code = 001, Name = Zara, Age = 9
Student Info: Code = 001, Name = Zara, Age = 10