C# Dictionary用法总结

http://blog.youkuaiyun.com/sunnykaho/article/details/4435568

C# Dictionary用法总结

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<String, String> pList = new Dictionary<String, String>();     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

/// <summary> /// Dictionary的Value为一个数组 /// </summary>  public static void DicSample2()  {      Dictionary<String, String[]> dic = new Dictionary<String, String[]>();      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<String, Student> stuList = new Dictionary<String, Student>();      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);      }  }

　　

Student类：

public class Student {     public String Num { get; set; }     public String Name { get; set; } }

　　

 4 备注：Dictionary的扩展方法使用

 

/// <summary> /// Dictionary的扩展方法使用 /// </summary>  public static void DicSample4()  {      //1)普通调用      Dictionary<int, String> dict = new Dictionary<int, String>();      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<int,int>();      dict1.AddOrPeplace(3, 3);      dict1.AddOrPeplace(5, 5);        var dict2 = new Dictionary<int, int>();      dict2.AddOrPeplace(1, 1);      dict2.AddOrPeplace(4, 4);      dict2.AddRange(dict1, false);  }

　　扩展方法所在的类

public static class DictionaryExtensionMethodClass {     /// <summary>     /// 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     /// </summary>     public static Dictionary<TKey, TValue> TryAdd<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue value)     {         if (dict.ContainsKey(key) == false)             dict.Add(key, value);         return dict;     }       /// <summary>     /// 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     /// </summary>     public static Dictionary<TKey, TValue> AddOrPeplace<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue value)     {         dict[key] = value;         return dict;     }       /// <summary>     /// 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     /// </summary>     public static TValue GetValue<TKey, TValue>(this Dictionary<TKey, TValue> dict, TKey key, TValue defaultValue)     {         return dict.ContainsKey(key)?dict[key] : defaultValue;     }       /// <summary>     /// 向字典中批量添加键值对     /// </summary>     /// <param name="replaceExisted">如果已存在，是否替换</param>     public static Dictionary<TKey, TValue> AddRange<TKey, TValue>(this Dictionary<TKey, TValue> dict, IEnumerable<KeyValuePair<TKey, TValue>> values, bool replaceExisted)     {         foreach (var item in values)         {             if (dict.ContainsKey(item.Key) == false || replaceExisted)                 dict[item.Key] = item.Value;         }         return dict;     }     }