//引入命名空间
using System;
using Examples;

namespace Examples
{
   public class Object1
   {
   }
}

public class Example
{
   public static void Main()
   {
      object obj1 = new Object1();
      Console.WriteLine(obj1.ToString());
   }
}

//引入命名空间
using System;

public class Object2
{
   private object value;
   
   public Object2(object value)
   {
      this.value = value;
   }
   
   public override string ToString()
   {
      return base.ToString() + ": " + value.ToString();
   }
}

public class Example
{
   public static void Main()
   {
      Object2 obj2 = new Object2('a');
      Console.WriteLine(obj2.ToString());
   }
}

//引入命名空间
using System;

public class Automobile
{
   private int _doors;
   private string _cylinders;
   private int _year;
   private string _model;

   public Automobile(string model, int year , int doors,
                     string cylinders)
   {
      _model = model;
      _year = year;
      _doors = doors;
      _cylinders = cylinders;
   }

   public int Doors
   { get { return _doors; } }

   public string Model
   { get { return _model; } }

   public int Year
   { get { return _year; } }

   public string Cylinders
   { get { return _cylinders; } }

   public override string ToString()
   {
      return ToString("G");
   }

   public string ToString(string fmt)
   {
      if (string.IsNullOrEmpty(fmt))
         fmt = "G";

      switch (fmt.ToUpperInvariant())
      {
         case "G":
            return string.Format("{0} {1}", _year, _model);
         case "D":
            return string.Format("{0} {1}, {2} dr.",
                                 _year, _model, _doors);
         case "C":
            return string.Format("{0} {1}, {2}",
                                 _year, _model, _cylinders);
         case "A":
            return string.Format("{0} {1}, {2} dr. {3}",
                                 _year, _model, _doors, _cylinders);
         default:
            string msg = string.Format("'{0}' is an invalid format string",
                                       fmt);
            throw new ArgumentException(msg);
      }
   }
}

public class Example
{
   public static void Main()
   {
      var auto = new Automobile("Lynx", 2016, 4, "V8");
      Console.WriteLine(auto.ToString());
      Console.WriteLine(auto.ToString("A"));
   }
}

//引入命名空间
using System;
using System.Globalization;

public class Example
{
   public static void Main()
   {
      string[] cultureNames = { "en-US", "en-GB", "fr-FR",
                                "hr-HR", "ja-JP" };
      Decimal value = 1603.49m;
      foreach (var cultureName in cultureNames) {
         CultureInfo culture = new CultureInfo(cultureName);
         Console.WriteLine("{0}: {1}", culture.Name,
                           value.ToString("C2", culture));
      }
   }
}

int[] values = { 1, 2, 4, 8, 16, 32, 64, 128 };
Console.WriteLine(values.ToString());

List<int> list = new List<int>(values);
Console.WriteLine(list.ToString());

//引入命名空间
using System;
using System.Collections.Generic;

public class CList<T> : List<T>
{
   public CList(IEnumerable<T> collection) : base(collection)
   { }

   public CList() : base()
   {}

   public override string ToString()
   {
      string retVal = string.Empty;
      foreach (T item in this) {
         if (string.IsNullOrEmpty(retVal))
            retVal += item.ToString();
         else
            retVal += string.Format(", {0}", item);
      }
      return retVal;
   }
}

public class Example
{
   public static void Main()
   {
      var list2 = new CList<int>();
      list2.Add(1000);
      list2.Add(2000);
      Console.WriteLine(list2.ToString());
   }
}

//引入命名空间
using System;
using System.Collections.Generic;

public static class StringExtensions
{
   public static string ToString2<T>(this List<T> l)
   {
      string retVal = string.Empty;
      foreach (T item in l)
         retVal += string.Format("{0}{1}", string.IsNullOrEmpty(retVal) ?
                                                     "" : ", ",
                                  item);
      return string.IsNullOrEmpty(retVal) ? "{}" : "{ " + retVal + " }";
   }

   public static string ToString<T>(this List<T> l, string fmt)
   {
      string retVal = string.Empty;
      foreach (T item in l) {
         IFormattable ifmt = item as IFormattable;
         if (ifmt != null)
            retVal += string.Format("{0}{1}",
                                    string.IsNullOrEmpty(retVal) ?
                                       "" : ", ", ifmt.ToString(fmt, null));
         else
            retVal += ToString2(l);
      }
      return string.IsNullOrEmpty(retVal) ? "{}" : "{ " + retVal + " }";
   }
}

public class Example
{
   public static void Main()
   {
      List<int> list = new List<int>();
      list.Add(1000);
      list.Add(2000);
      Console.WriteLine(list.ToString2());
      Console.WriteLine(list.ToString("N0"));
   }
}