using System;
using System.Diagnostics;
using System.Text;
using System.Collections;
using System.Collections.Generic;
delegate string DTE(int x, string s);class MYTestX
{public class CDT{public CDT(int x){this.x = x;}int x = 10;//类型转换只能是public static implicit形式或public static explicit形式//，这里的implicit与explicit并不是返回值类型，而是修饰符，说明是隐式转换还是显式转换//因此不能写成public static bool operator bool(CDT odt)这样的形式，编译会出错//应用场景 //1: CDT ot = new CDT(); if(ot){}//2: CDT ot = new CDT(); bool b = ot;public static implicit operator bool(CDT odt){Console.WriteLine("operator bool------------------");return odt != null;}//应用场景：//CDT ot = new CDT(); string s = (string) otpublic static explicit operator string(CDT odt){Console.WriteLine("operator string------------------");return odt.ToString();}//应用场景：//CDT ot = new CDT(); string s = otpublic static implicit operator int(CDT odt){Console.WriteLine("operator string------------------");return odt.x;}//重载 true false运算符（注意的MSDN文档说明中说true和false是运算符，就像 +,-普通运算符一样)//两者必须一起重载。其实就相当于重载一个bool运算符的效果, 并不完全等价//应用场景：//CDT ot = new CDT(); if(ot){}//不能用于: CDT ot = new CDT();  bool b = ot; bool b2 = (bool)ot;public static bool operator true(CDT odt){return odt != null;}public static bool operator false(CDT odt){return odt == null;}}class CDTX { }//public void TestLimitX(CDTX ot)//编译错误：CDTX的访问权限不能小于TestLimitX的访问权限//{//}public static void TestLimit(CDT ot)//可以访问
    {if (ot) { }//调用operator turebool b = ot;//调用operator bool，若无此重载，则编译错误，并不会调用operator ture 或ooperator falsestring st = (string)ot; //可以转换，调用重载的显示的string转换运算符CDTX otx = new CDTX();//string stx = (string)otx; //编译出错，不能转换
        Console.WriteLine(b);}static void Main(string[] args){TestLimit(new CDT(112));}}