属性(Properties)被命名为类，结构和接口的成员。类或结构中的成员变量或方法称为字段。 属性是字段的扩展，并使用相同的语法访问。它们使用访问器，通过这些访问器可以读取，写入或操作私有字段的值。
属性不指定存储位置。它们有读取，写入或计算其值的访问器。
例如，假设有一个名称为Student的类，其中包含年龄(age)，名称(name)和代码(code)的私有字段。我们无法从类范围外直接访问这些字段，但是可以拥有访问这些私有字段的属性。
访问器
属性的访问器包含有助于获取(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访问器和set访问器。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
}
}
例子
以下示例演示了如何使用属性：
using System
namespace yiibai
{
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 = "10010"
s.Name = "Maxsu"
s.Age = 24
Console.WriteLine("Student Info: {0}", s)
//let us increase age
s.Age += 1
Console.WriteLine("Student Info: {0}", s)
Console.ReadKey()
}
}
}
当上述代码被编译并执行时，它产生以下结果：
Student Info: Code = 10010, Name = Maxsu, Age = 24
Student Info: Code = 10010, Name = Maxsu, Age = 25
抽象属性
抽象类可能有一个抽象属性，它应该在派生类中实现。以下程序说明了这一点：
using System
namespace yiibai
{
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 = "1011"
s.Name = "Maxsu"
s.Age = 21
Console.WriteLine("Student Info:- {0}", s)
//let us increase age
s.Age += 1
Console.WriteLine("Student Info:- {0}", s)
Console.ReadKey()
}
}
}
当上述代码被编译并执行时，它产生以下结果：
Student Info:- Code = 1011, Name = Maxsu, Age = 21
Student Info:- Code = 1011, Name = Maxsu, Age = 22