C# Dictionary 用法；

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;    }    }

C# Dictionary 用法；

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