C# Dictionary用法总结

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1、用法1: 常规用

publicstatic voidDicSample1()
{
 
    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 inpList.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>
 publicstatic voidDicSample2()
 {
     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
publicstatic voidDicSample3()
 {
     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:

publicclass Student
{
    publicString Num { get;set; }
    publicString Name { get;set; }
}

  

 4 备注:Dictionary的扩展方法使用

 

/// <summary>
/// Dictionary的扩展方法使用
/// </summary>
 publicstatic voidDicSample4()
 {
     //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
     varv1 = dict.GetValue(111,null);
     varv2 = dict.GetValue(10,"abc");
 
     //6)批量添加
     vardict1 = newDictionary<int,int>();
     dict1.AddOrPeplace(3, 3);
     dict1.AddOrPeplace(5, 5);
 
     vardict2 = newDictionary<int,int>();
     dict2.AddOrPeplace(1, 1);
     dict2.AddOrPeplace(4, 4);
     dict2.AddRange(dict1,false);
 }

  扩展方法所在的类

publicstatic classDictionaryExtensionMethodClass
{
    /// <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>
    publicstatic Dictionary<TKey, TValue> TryAdd<TKey, TValue>(thisDictionary<TKey, TValue> dict, TKey key, TValue value)
    {
        if(dict.ContainsKey(key) == false)
            dict.Add(key, value);
        returndict;
    }
 
    /// <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>
    publicstatic Dictionary<TKey, TValue> AddOrPeplace<TKey, TValue>(thisDictionary<TKey, TValue> dict, TKey key, TValue value)
    {
        dict[key] = value;
        returndict;
    }
 
    /// <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>
    publicstatic TValue GetValue<TKey, TValue>(thisDictionary<TKey, TValue> dict, TKey key, TValue defaultValue)
    {
        returndict.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>
    publicstatic Dictionary<TKey, TValue> AddRange<TKey, TValue>(thisDictionary<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;
        }
        returndict;
    }
 
 
}
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