用法一：
父类的结构函数总是在子类之前执行的。既先初始化静态结构函数，后初始化子类结构函数。
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); ｝
输出功效： 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，此刻我来写份代码，代码可是最有说服力的啦！
class BaseClass { private int numA; public BaseClass() { Console.WriteLine("基类的无参数结构函数. value:{0}", numA); } public BaseClass(int i) { this.numA = i; Console.WriteLine("基类带一个参数的结构函数. value:{0}", numA); } } class ChildClassA : BaseClass { private int numB; public ChildClassA() { Console.WriteLine("子类无参数结构函数. value:{0}", numB); } public ChildClassA(int i) { this.numB = i; Console.WriteLine("子类带有一个参数的结构函数. 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结构函数. value:{0}", numB); } } class ChildClassB : BaseClass { private int numB; public ChildClassB() { Console.WriteLine("子类无参数结构函数. value:{0}", numB); } public ChildClassB(int i) { this.numB = i; Console.WriteLine("子类带有一个参数的结构函数. 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结构函数. 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(); } }
执行的功效如下：