Dictionary

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

namespace DictionaryDemo
{
    class Program
    {
        static void Main(string[] args)
        {
            DictionarySample();
            Console.ReadLine();
        }

        static void DictionarySample()
        {
            //宣告 Dictionary 時候順便加東西
            Dictionary<string, Gamer> dictionaryGamers = new Dictionary<string, Gamer>
            {
                {"Key1", new Gamer {Id = 1, Name = "Name1", Email = "[email protected]"}},
                {"Key2", new Gamer {Id = 2, Name = "Name2", Email = "[email protected]"}}
            };
            //宣告 Dictionary 之後再加東西
            dictionaryGamers.Add("Key3", new Gamer { Id = 3, Name = "Name3", Email = "[email protected]" });
            dictionaryGamers.Add("Key4", new Gamer { Id = 4, Name = "Name4", Email = "[email protected]" });

            Console.WriteLine($"dictionaryGamers.Count = {dictionaryGamers.Count}");
            Console.WriteLine($"包含：");
            #region Dictionary.FirstOrDefault
            KeyValuePair<string, Gamer> key1Value = dictionaryGamers.FirstOrDefault(g => g.Key == "Key1");
            Gamer gamer1 = dictionaryGamers.FirstOrDefault(g => g.Key == "Key1").Value;
            KeyValuePair<string, Gamer> key2Value = dictionaryGamers.FirstOrDefault(x => x.Key == "Key2");
            Console.WriteLine($"key1Value.Key : {key1Value.Key}  ;  " + $"key1Value.Value.ToString() : {key1Value.Value.ToString()}");
            Console.WriteLine($"key2Value.Key : {key2Value.Key}  ;  " + $"key2Value.Value.ToString() : {key2Value.Value}");
            #endregion
            #region Dictionary.FirstOrDefault
            KeyValuePair<string, Gamer> lastItem = dictionaryGamers.Last();
            Console.WriteLine("");
            Console.WriteLine("最後一個為：");
            Console.WriteLine($"lastItem.Key : {lastItem.Key}  ;  " + $"lastItem.Value.ToString() : {lastItem.Value}");
            #endregion
            Console.WriteLine("========================================================================================================================");
            Dictionary<string, string> A = new Dictionary<string, string>();
            A.Add("ID_1", "Name_1");//Index = 0
            A.Add("ID_2", "Name_2");//Index = 1
            A.Add("ID_3", "Name_3");//Index = 2

            #region Dictionary.ElementAt
            Console.WriteLine("");
            Console.WriteLine("Dictionary.ElementAt(Dictionary.Count - 1)");
            var obj = A.ElementAt(A.Count - 1);
            Console.WriteLine($"A{A.Count - 1}.Key = {obj.Key}");
            Console.WriteLine($"A{A.Count - 1}.Value = {obj.Value}");
            #endregion

            #region Dictionary.Keys.ElementAt
            Console.WriteLine("");
            Console.WriteLine("Dictionary.Keys.ElementAt(Dictionary.Count - 1)");
            string temp = A.Keys.ElementAt(A.Count - 1);
            Console.WriteLine($"A{A.Count - 1}.Key = {temp}");
            Console.WriteLine($"A{A.Count - 1}.Value = {A[temp]}");
            #endregion

            #region foreach(var item in Dictionary){...}
            Console.WriteLine("");
            Console.WriteLine("foreach(var item in Dictionary){...}");
            foreach (var item in A)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion

            #region Dictionary.ContainsKey
            Console.WriteLine("");
            Console.WriteLine("Dictionary.ContainsKey(KEY)");
            if (!A.ContainsKey("ID_4"))
            {
                A.Add("ID_4", "Name_4");
            }

            foreach (var item in A)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion

            #region Dictionary.Remove
            Console.WriteLine("");
            Console.WriteLine("Dictionary.Remove(KEY)");
            A.Remove("ID_4");
            foreach (var item in A)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion

            #region Dictionary.Clear()
            Console.WriteLine("");
            Console.WriteLine("Dictionary.Clear()");
            A.Clear();
            Console.WriteLine($"A.Count = {A.Count}");
            #endregion

            Console.WriteLine("");
            Console.WriteLine("========================================================================================================================");
            Console.WriteLine("ArrayObject.ToDictionary()");
            Gamer[] customersArr = {
                new Gamer {Id = 1, Name = "Name1", Email = "[email protected]"},
                new Gamer {Id = 2, Name = "Name2", Email = "[email protected]"},
                new Gamer {Id = 3, Name = "Name3", Email = "[email protected]" },
                new Gamer {Id = 4, Name = "Name4", Email = "[email protected]" }
            };

            #region 方法一
            Console.WriteLine("方法一：");
            Dictionary<int, Gamer> dictionaryGamers1 = customersArr.ToDictionary(gamerItem => gamerItem.Id//Key
                , gamerItem => gamerItem//Vallue
            );
            foreach (KeyValuePair<int, Gamer> item in dictionaryGamers1)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion

            #region 方法二
            Console.WriteLine("");
            Console.WriteLine("方法二：");
            Dictionary<int, Gamer> dictionaryGamers2 = customersArr.ToDictionary(gamerItem => gamerItem.Id);
            foreach (KeyValuePair<int, Gamer> item in dictionaryGamers2)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion

            #region 方法三
            Console.WriteLine("");
            Console.WriteLine("方法三：（此種方式最常見）");
            Dictionary<int, Gamer> dictionaryGamers3 = new Dictionary<int, Gamer>();
            foreach (Gamer gamerItem in customersArr)
            {
                dictionaryGamers3.Add(gamerItem.Id, gamerItem);
            }
            foreach (KeyValuePair<int, Gamer> item in dictionaryGamers3)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion

            #region 方法四
            Console.WriteLine("");
            Console.WriteLine("方法四：");
            Dictionary<int, Gamer> dictionaryGamers4 = new Dictionary<int, Gamer>();
            for (int index = 0; index < customersArr.Length; index++)
            {
                Gamer gamerItem = customersArr[index];
                dictionaryGamers4.Add(gamerItem.Id, gamerItem);
            }
            foreach (KeyValuePair<int, Gamer> item in dictionaryGamers4)
            {
                Console.WriteLine($"item.Key == {item.Key}   ;   item.Value : {item.Value}");
            }
            #endregion
        }
    }
}

namespace OnLineGame
{
    // 1. ---------------------------------------------
    public class Gamer
    {
        public int Id { get; set; }
        public string Name { get; set; }
        public string Email { get; set; }
        public override string ToString()
        {
            return $"Id == {Id} ; Name == {Name} ; Email : {Email}";
        }
    }
}