深入.NET和c#理解---第三章技能知识点(ArrayList/Hashtable/泛型集合)-优快云博客

本文链接：https://blog.youkuaiyun.com/qq_36074113/article/details/55050089

本文介绍C#中集合的使用方法，包括ArrayList的基本操作、自动扩容机制、集合初始化器的应用，以及Dictionary泛型集合的多种遍历方式。演示了如何创建、添加、修改、删除集合中的元素。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_01集合初步
{
    class Book
    {
        public string BookName { get; set; }
        public string BookAuthor { get; set; }
        public int BookPrice { get; set; }
        public Book() { }
        public Book(string bookname, string bookauthor, int bookprice)
        {
            this.BookName = bookname;
            this.BookAuthor = bookauthor;
            this.BookPrice = bookprice;
        }
    }
}


using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_01集合初步
{
    class Program
    {
        static void Main(string[] args)
        {
            //ListBeginOneDemo();
            ForeachTest();
            foreach (Book item in list)
            {
               
                if (item.BookAuthor.Equals("韩寒"))
                {
                    item.BookAuthor = "郭敬明";
                    break;
                }
            }
            Console.WriteLine("===================修改===============");
            foreach (Book item in list)
            {
                Console.WriteLine(item.BookAuthor);
            }
        }

        private static void ListBeginOneDemo()
        { 
        
            ArrayList list= new ArrayList();
            list.Add("宋小宝");
            list.Add("张靓颖");
            list.Add("徐小倩");
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }

            for (int i = 0; i < list.Count; i++)
            {
                if (list[i].Equals("宋小宝"))
                {
                    list[i] = "JustinBiber";
                    break;
                }
            }

            Console.WriteLine("修改后==========");
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }
            Console.WriteLine("删除=========分割线=========");
            list.Remove("徐小倩");
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }
            Console.WriteLine("根据索引删除=========分割线=========");
            Console.WriteLine("张靓颖");
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }
            Console.WriteLine("删除所有=========分割线=========");
            list.Clear();
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }

        }

        //使用foreach修改引用的值
        static ArrayList list = new ArrayList();
        private static void ForeachTest()
        {

            Book book1 = new Book("你是人间的四月天", "林微因", 50);
            Book book2 = new Book("艰难的抉择", "卡莉·菲奥莉娜", 60);
            Book book3 = new Book("三重门", "韩寒", 70);

            list.Add(book1);
            list.Add(book2);
            list.Add(book3);
            foreach (Book item in list)
            {
                Console.WriteLine(item.BookAuthor);
            }
        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_02自动扩容
{

    /*
             * 自动扩容：
             * 如果结合中一个元素都没有，Capacity为0，
             * 如果集合中出现第一个元素，分配4个空间，
             * 如果出现第5个元素的时候，可以容纳8个元素，
             * 每次扩容会扩成上次的2倍             
             */


    class Program
    {
        static void Main(string[] args)
        {
            
            ArrayList list = new ArrayList();

            list.Add(1);
            list.Add(2);
            list.Add(2);
            list.Add(2);
            list.Add(3);

            foreach (Object item in list)
            {

                Console.WriteLine(item);
            }

            Console.WriteLine(list.Capacity + "   容量");  //  6
            Console.WriteLine(list.Count + " 真正存储元素个数");//5
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_03集合初始化器
{
    class Book
    {
        public string Anthor { get; set; }
        public string BookName { get; set; }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_03集合初始化器
{
    class Program
    {
        static void Main(string[] args)
        {
            //对象初始化器
            Book book = new Book() { Anthor="蝎子木二口",BookName="邪恶的力量"};
            ArrayList list = new ArrayList()
            {

                book
            };

            Console.WriteLine(list);

        }
    }
}

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_04Dictionary双列集合
{
    class Program
    {
        static void Main(string[] args)
        {
            Hashtable table = new Hashtable();
            table.Add("CBC", "建设银行");
            table.Add("ABC", "中国农业银行");
            table.Add("ICBC", "工商银行");

            //方式一:通过Key便利Value
            foreach (string key in table.Keys)
            {
                Console.WriteLine("Key是"+key);
                object values = table[key];
                Console.WriteLine("Values是"+values);
            }
            //方式二：直接遍历value
            foreach (string value in table.Values)
            {
                Console.WriteLine(value);
            }

            //方法三:key和Value一次遍历一个项目
            foreach (DictionaryEntry item in table)
            {
                Console.WriteLine(item.Key + " " + item.Value);
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_05_单列泛型集合DictionaryT
{
    class Program
    {
        static void Main(string[] args)
        {
            List<string> list = new List<string>();
            //添加
            list.Add("baby");
            list.Add("love");
            list.Add("me");
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }
            //删除
            Console.WriteLine("=====================");
            list.Remove("me");
            foreach (string item in list)
            {
                Console.WriteLine(item);
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_06_泛型集合DictionaryTV
{
   public  class Book
    {
        public string BookId { get; set; }
        public string  BookName { get; set; }
        public int Price { get; set; }
        
    }
}


using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace _03_06_泛型集合DictionaryTV
{
    class Program
    {
        static void Main(string[] args)
        {
            Dictionary<string, Book> div = new Dictionary<string, Book>();
            //初始化器
            Book book1 = new Book() { BookId = "001", BookName = "战争与和平", Price =56 };
            Book book2 = new Book() { BookId = "002", BookName = "狂人日记", Price = 78 };
            Book book3 = new Book() { BookId = "003", BookName = "百年孤独", Price = 98 };

            //添加
            div.Add(book1.BookId, book1);
            div.Add(book2.BookId, book2);
            div.Add(book3.BookId, book3);
            //根据key值获得values
            foreach (string item in div.Keys)
            {
                Console.WriteLine("key是" + item);
                //获取value
                Book book = div[item];
                Console.WriteLine(book.BookName);
            }
            //直接获取value
            foreach (Book item in div.Values)
            {
                Console.WriteLine("图书的名称" + item.BookName);
            }

            // key 和 value
            foreach (KeyValuePair<string, Book> item in div)
            {

                Console.WriteLine(item.Key);
               
                Console.WriteLine(item.Value.BookName);
            }
        }
    }
}