解释一下代码

Question

 public PersonController()            : this(new PersonBLL()) { }

Answer 1

 using System;
  2 using System.Collections.Generic; 
  3 using System.Linq;
  4 using System.Text;
   5 
    6 
    namespace ConsoleApplication1
     7 
     {
      8  
        class Program
        9    
         {
         10       
           static void Main(string[] args)11     
               {12             PersonBLL p = new PersonBLL();
               13    
                        PersonController pc = new PersonController(p); //初始化带参构造函数14         
                            //输出：初始化了带参构造函数15             Console.WriteLine("---------------------------------");16             PersonController pc1 = new PersonController();//初始化无参构造函数17             //输出：初始化了带参构造函数18             //      初始化了无参构造函数19         }20     }21 22     public class PersonController23     {24         private PersonBLL personBLL;25 26         public PersonController(PersonBLL p)27         {28             this.personBLL = p;29             Console.WriteLine("初始化了带参构造函数");30         }31 32         public PersonController()33             : this(new PersonBLL())34         {35             Console.WriteLine("初始化了无参构造函数");36         }37     }38 39     public class PersonBLL40     {41     }42 }

在调用无惨构造函数的时候，会先初始化带参构造函数，再明白了吧

Answer 2

PersonController类里面有一个构造函数 public PersonController(PersonBLL p)

直接调用该构造函数初始化了public PersonController()