Dictionary键值对的使用

abstract：using System;using System.Collections.Generic;using System.Linq;using System.Text;namespace Dictionary键值对 { class Program { &n

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

namespace Dictionary键值对 { class Program { static void Main(string[] args) { DicSample1(); DicSample2(); DicSample3(); DicSample4(); Console.Read(); } //1、用法1：　常规用 //　　增加键值对之前需要判断是否存在该键，如果已经存在该键而且不判断，将抛出异常。所以这样每次都要进行判断，很麻烦，在备注里使用了一个扩展方法 public static void DicSample1() { Dictionary pList = new Dictionary(); try { if (pList.ContainsKey("Item1") == false) { pList.Add("Item1", "ZheJiang"); } if (pList.ContainsKey("Item2") == false) { pList.Add("Item2", "ShangHai"); } else { pList["Item2"] = "ShangHai"; } if (pList.ContainsKey("Item3") == false) { pList.Add("Item3", "BeiJiang"); } } catch (System.Exception e) { Console.WriteLine("Error: {0}", e.Message); } //判断是否存在相应的key并显示 if (pList.ContainsKey("Item1")) { Console.WriteLine("Output: " + pList["Item1"]); } //遍历Key foreach (var key in pList.Keys) { Console.WriteLine("Output Key: {0}", key); } //遍历Value foreach (String value in pList.Values) { Console.WriteLine("Output Value: {0}", value); } //遍历Key和Value foreach (var dic in pList) { Console.WriteLine("Output Key : {0}, Value : {1} ", dic.Key, dic.Value); } } //2、用法2：Dictionary的Value为一个数组 /// 
 /// Dictionary的Value为一个数组 /// 
 public static void DicSample2() { Dictionary dic = new Dictionary(); String[] ZheJiang = { "Huzhou", "HangZhou", "TaiZhou" }; String[] ShangHai = { "Budong", "Buxi" }; dic.Add("ZJ", ZheJiang); dic.Add("SH", ShangHai); Console.WriteLine("Output :" + dic["ZJ"][0]); } //3、用法3： Dictionary的Value为一个类 //Dictionary的Value为一个类 public static void DicSample3() { Dictionary stuList = new Dictionary(); Student stu = null; for (int i = 0; i < 3; i++) { stu = new Student(); stu.Name = i.ToString(); stu.Name = "StuName" + i.ToString(); stuList.Add(i.ToString(), stu); } foreach (var student in stuList) { Console.WriteLine("Output : Key {0}, Num : {1}, Name {2}", student.Key, student.Value.Name, student.Value.Name); } } //4 备注：Dictionary的扩展方法使用 /// 
 /// Dictionary的扩展方法使用 /// 
 public static void DicSample4() { //1)普通调用 Dictionary dict = new Dictionary(); DictionaryExtensionMethodClass.TryAdd(dict, 1, "ZhangSan"); DictionaryExtensionMethodClass.TryAdd(dict, 2, "WangWu"); DictionaryExtensionMethodClass.AddOrPeplace(dict, 3, "WangWu"); DictionaryExtensionMethodClass.AddOrPeplace(dict, 3, "ZhangWu"); DictionaryExtensionMethodClass.TryAdd(dict, 2, "LiSi"); //2)TryAdd 和 AddOrReplace 这两个方法具有较强自我描述能力，用起来很省心，而且也简单： dict.AddOrPeplace(20, "Orange"); dict.TryAdd(21, "Banana"); dict.TryAdd(22, "apple"); //3)像Linq或jQuery一样连起来写 dict.TryAdd(10, "Bob") .TryAdd(11, "Tom") .AddOrPeplace(12, "Jom"); //4) 获取值 String F = "Ba"; dict.TryGetValue(31, out F); Console.WriteLine("F : {0}", F); foreach (var dic in dict) { Console.WriteLine("Output : Key : {0}, Value : {1}", dic.Key, dic.Value); } //5)下面是使用GetValue获取值 var v1 = dict.GetValue(111, null); var v2 = dict.GetValue(10, "abc"); //6)批量添加 var dict1 = new Dictionary(); dict1.AddOrPeplace(3, 3); dict1.AddOrPeplace(5, 5); var dict2 = new Dictionary(); dict2.AddOrPeplace(1, 1); dict2.AddOrPeplace(4, 4); dict2.AddRange(dict1, false); } } //Student类： public class Student { public String Num { get; set; } public String Name { get; set; } } //扩展方法所在的类 public static class DictionaryExtensionMethodClass { /// 
 /// 尝试将键和值添加到字典中：如果不存在，才添加；存在，不添加也不抛导常 /// 
 public static Dictionary TryAdd(this Dictionary dict, TKey key, TValue value) { if (dict.ContainsKey(key) == false) dict.Add(key, value); return dict; } /// 
 /// 将键和值添加或替换到字典中：如果不存在，则添加；存在，则替换 /// 
 public static Dictionary AddOrPeplace(this Dictionary dict, TKey key, TValue value) { dict[key] = value; return dict; } /// 
 /// 获取与指定的键相关联的值，如果没有则返回输入的默认值 /// 
 public static TValue GetValue(this Dictionary dict, TKey key, TValue defaultValue) { return dict.ContainsKey(key) ? dict[key] : defaultValue; } /// 
 /// 向字典中批量添加键值对 /// 
 /// 如果已存在，是否替换 public static Dictionary AddRange(this Dictionary dict, IEnumerable> values, bool replaceExisted) { foreach (var item in values) { if (dict.ContainsKey(item.Key) == false || replaceExisted) dict[item.Key] = item.Value; } return dict; } } }