用法一：
父类的构造函数总是在子类之前执行的。既先初始化静态构造函数，后初始化子类构造函数。
public
class BaseCircle { public
BaseCircle() { Console.WriteLine(" no arguments base constructor!!!"); } public
BaseCircle(double
arg) { Console.WriteLine("double arg base constructor!!!"); } } public
class SubCircle : BaseCircle { public
SubCircle():base() { Console.WriteLine("sub class no argument constructor,actually call base constructor !!!"); } public
SubCircle(double
a):base(a) { Console.WriteLine("sub class with argument, actually call base double constructor!!!"); } public
SubCircle(int
k):this(1,2) { Console.WriteLine("sub class with argument int k, actually call sub class constructor int i & j !!!"); } public
SubCircle(int
i,int
j) { Console.WriteLine("sub class with int i&j argument!!!!"); } }static
void Main(string[] args) { SubCircle s1 = new
SubCircle(); SubCircle s2 = new
SubCircle(1.1); SubCircle s3 = new
SubCircle(1);｝输出结果： no arguments base
constructor!!!sub class
no argument constructor,actually call base
constructor !!!double
arg base
constructor!!!sub class
with argument, actually call base
double constructor!!! no arguments base
constructor!!!sub class
with int
i&j argument!!!!sub class
with argument int
k, actually call sub class
constructor int
i & j !!! |
用法二：
是不是很模糊这两个关键字那？哈，现在我来写份代码，代码可是最有说服力的啦！ class
BaseClass { private
int numA; public
BaseClass() { Console.WriteLine("基类的无参数构造函数. value:{0}", numA); } public
BaseClass(int
i) { this.numA = i; Console.WriteLine("基类带一个参数的构造函数. value:{0}", numA); } } class
ChildClassA : BaseClass { private
int numB; public
ChildClassA() { Console.WriteLine("子类无参数构造函数. value:{0}", numB); } public
ChildClassA(int
i) { this.numB = i; Console.WriteLine("子类带有一个参数的构造函数. value:{0}", numB); } public
ChildClassA(int
i, int
j) : base(i) { this.numB = j; Console.WriteLine("子类带有两个参数的构造函数. value:{0}", numB); } } class
ChildClassB : BaseClass { private
int numB; public
ChildClassB() { Console.WriteLine("子类无参数构造函数. value:{0}", numB); } public
ChildClassB(int
i) { this.numB = i; Console.WriteLine("子类带有一个参数的构造函数. value:{0}", numB); } public
ChildClassB(int
i, int
j) : this(i) { this.numB = j; Console.WriteLine("子类带有两个参数的构造函数. value:{0}", numB); } } class
Demo { static
void Main(string[] args) { Console.WriteLine("使用base\n"); ChildClassA a = new
ChildClassA(2, 4); Console.WriteLine(); Console.WriteLine("----------------------------------------\n"); Console.WriteLine("使用this\n"); ChildClassB b = new
ChildClassB(2, 4); Console.ReadKey(); } }执行的结果如下：--------------------------------结果----------------------------------使用base基类带一个参数的构造函数. value:2子类带有两个参数的构造函数. value:4----------------------------------------使用this基类的无参数构造函数. value:0子类带有一个参数的构造函数. value:2子类带有两个参数的构造函数. value:4--------------------------------结果----------------------------------this只是调用本身，但是这样是需要调用一次基类没有参的构造函数，所以会多显示一条“基类的无参数构造函数. value:0”。base是调用基类的有参数构造函数。够简洁明了吧，看了就懂，希望能给网友一些帮助。 |
C#构造函数里的base和this的区别,布布扣,bubuko.com
原文：http://www.cnblogs.com/zfanlong1314/p/3591453.html