C#实现自定义Dictionary类实例

本文实例讲述了C#实现自定义Dictionary类。分享给大家供大家参考。具体如下：

1.关于MyDictionary类

本文中实现的MyDictionary类具有如下功能

1）可以增加、修改、删除键值对
2）可以通过索引器，找到一个键对应的值
3）可以遍历打印类中全部的键值对
4）可以将类中的序列转化为有序的（不排序、升序、降序）List类型

MyDictionary类是一个具有两个参数的泛型类，内部机制采用以键值对（KeyValuePair）类型为元素的双向链表（LinkedList）实现

2.实现代码

class MyDictioinary<TKey, TValue>
{
 LinkedList<KeyValuePair<TKey, TValue>> llDictionary
  = new LinkedList<KeyValuePair<TKey, TValue>>();
 /// <summary>
 /// 索引器，输入TKey可以找到对应的TValue
 /// </summary>
 /// <param name="tk">键值</param>
 /// <returns></returns>
 public TValue this[TKey tk]
 {
  get
  {
   foreach(KeyValuePair<TKey, TValue> kvp in llDictionary)
   {
    if (tk.Equals(kvp.Key))
    {
     return kvp.Value;
    }
   }
   return default(TValue);
  }
 }
 /// <summary>
 /// 添加一组数据
 /// </summary>
 /// <param name="tk"></param>
 /// <param name="tv"></param>
 public void Add(TKey tk, TValue tv)
 {
  foreach (KeyValuePair<TKey, TValue> kvp in llDictionary)
  {
   if (tk.Equals(kvp.Key))
   {
    throw new Exception("新增失败：主键已经存在");
   }
  }
  llDictionary.AddLast(new KeyValuePair<TKey, TValue>(tk, tv));
 }
 /// <summary>
 /// 删除一组数据
 /// </summary>
 /// <param name="tk"></param>
 public void Delete(TKey tk)
 {
  foreach (KeyValuePair<TKey, TValue> kvp in llDictionary)
  {
   if (tk.Equals(kvp.Key))
   {
    llDictionary.Remove(kvp);
    return;
   } 
  }
  throw new Exception("删除失败：不存在这个主键");
 }
 /// <summary>
 /// 修改一组数据
 /// </summary>
 /// <param name="tk"></param>
 /// <param name="tv"></param>
 public void Modify(TKey tk, TValue tv)
 {
  LinkedListNode<KeyValuePair<TKey, TValue>> lln = llDictionary.First;
  while (lln != null )
  {
   if (tk.Equals(lln.Value.Key))
   {
    llDictionary.AddBefore(lln, new KeyValuePair<TKey, TValue>(tk, tv));
    llDictionary.Remove(lln);
    return;
   }
   lln = lln.Next;
  }
  throw new Exception("修改失败：不存在这个主键");
 }
 /// <summary>
 /// 打印整个Dictionary内的全部数据
 /// </summary>
 public void PrintData()
 {
  Console.WriteLine("==================");
  Console.WriteLine("输出数据");
  Console.WriteLine("==================");
  foreach (KeyValuePair<TKey, TValue> kvp in llDictionary)
  {
   Console.WriteLine(kvp.Key.ToString() + "\t:" + kvp.Value.ToString());
  }
  Console.WriteLine(string.Format("共计输出 {0} 项", llDictionary.Count));
  Console.WriteLine(DateTime.Now.ToLongTimeString());
  Console.WriteLine("==================");
 }
 /// <summary>
 /// 决定按什么顺序打印Dictionary内的数据
 /// </summary>
 public enum PrintType
 {
  Normal = 0, //不排序
  Ascend = 1, //升序排列
  Descend = 2 //降序佩列
 };
 /// <summary>
 /// 返回List类型的数据
 /// </summary>
 /// <param name="printType">List内数据的排序情况</param>
 /// <returns></returns>
 public List<KeyValuePair<TKey, TValue>> ToList(PrintType printType = PrintType.Normal)
 {
  switch (printType)
  {
   case PrintType.Normal:
    {
     return llDictionary.ToList();
    }
   case PrintType.Ascend:
    {
     if (llDictionary.Count == 0) return null;
     LinkedList<KeyValuePair<TKey, TValue>> newll = 
      new LinkedList<KeyValuePair<TKey, TValue>>();
     try
     {
      LinkedListNode<KeyValuePair<TKey, TValue>> lln = llDictionary.First;
      while (lln != null)
      {
       LinkedListNode<KeyValuePair<TKey, TValue>> lln2 = newll.First;
       while (lln2 != null)
       {
        //Key是字符串的情况
        if (llDictionary.First.Value.Key.GetType() == 
         "string".GetType())
        {
         if (string.Compare(lln2.Value.Key.ToString(),
          lln.Value.Key.ToString()) > 0)
         {
          newll.AddBefore(lln2, new LinkedListNode
           <KeyValuePair<TKey, TValue>>(lln.Value));
          break;
         }
        }
        else //Key可以被转化为浮点数的情况
        {
         if (double.Parse(lln2.Value.Key.ToString()) >
          double.Parse(lln.Value.Key.ToString()))
         {
          newll.AddBefore(lln2, new LinkedListNode
           <KeyValuePair<TKey, TValue>>(lln.Value));
          break;
         }
        }
        lln2 = lln2.Next;
       }
       if (lln2 == null)
       {
        newll.AddLast(new LinkedListNode
         <KeyValuePair<TKey, TValue>>(lln.Value));
       }
       lln = lln.Next;
      }
     }
     catch (Exception ex)
     {
      Console.WriteLine(ex.Message);
     }
     return newll.ToList();
    }
   case PrintType.Descend:
    {
     if (llDictionary.Count == 0) return null;
     LinkedList<KeyValuePair<TKey, TValue>> newll =
      new LinkedList<KeyValuePair<TKey, TValue>>();
     try
     {
      LinkedListNode<KeyValuePair<TKey, TValue>> lln = llDictionary.First;
      while (lln != null)
      {
       LinkedListNode<KeyValuePair<TKey, TValue>> lln2 = newll.First;
       while (lln2 != null)
       {
        //Key是字符串的情况
        if (llDictionary.First.Value.Key.GetType() == 
         "string".GetType())
        {
         if (string.Compare(lln2.Value.Key.ToString(),
          lln.Value.Key.ToString()) < 0)
         {
          newll.AddBefore(lln2, new LinkedListNode
           <KeyValuePair<TKey, TValue>>(lln.Value));
          break;
         }
        }
        else //Key可以被转化为浮点数的情况
        {
         if (double.Parse(lln2.Value.Key.ToString()) <
          double.Parse(lln.Value.Key.ToString()))
         {
          newll.AddBefore(lln2, new LinkedListNode
           <KeyValuePair<TKey, TValue>>(lln.Value));
          break;
         }
        }
        lln2 = lln2.Next;
       }
       if (lln2 == null)
       {
        newll.AddLast(new LinkedListNode
         <KeyValuePair<TKey, TValue>>(lln.Value));
       }
       lln = lln.Next;
      }
     }
     catch (Exception ex)
     {
      Console.WriteLine(ex.Message);
     }
     return newll.ToList();
    }
   default: return null;
  }
 }
}

3.Main函数调用示例

static void Main(string[] args)
{
 MyDictioinary<string, string> dic = new MyDictioinary<string, string>();
 //插入两组数据
 dic.Add("1", "MERCURY");
 dic.Add("2", "VENUS");
 //尝试插入重复主键的数据 报警：主键不存在
 try
 {
  dic.Add("1", "EARTH");
 }
 catch (Exception ex)
 {
  Console.WriteLine(ex.Message);
 }
 //删除一组数据
 dic.Delete("1");
 //添加一组数据
 dic.Add("1", "MARS");
 //修改两组数据
 dic.Modify("1", "JUPITER");
 dic.Modify("2", "SATURN");
 //添加两组数据
 dic.Add("6", "SUN");
 dic.Add("5", "MOON");
 dic.Add("8", "URANUS");
 dic.Add("9", "NEPTUNE");
 dic.PrintData();
 //通过索引找到对应值
 Console.WriteLine("key为6的元素value为：" + dic["6"]);
 Console.WriteLine("key为3的元素value为：" + dic["3"]);
 List<KeyValuePair<string, string>> l;
 //输出升序排列好的List
 l = dic.ToList(MyDictioinary<string, string>.PrintType.Ascend);
 Console.WriteLine("升序排列后的List：");
 for (int i = 0; i < l.Count; i++)
 {
  Console.WriteLine(l[i].Key.ToString() + "\t:" + l[i].Value.ToString());
 }
 //输出降序排列好的List
 l = dic.ToList(MyDictioinary<string, string>.PrintType.Descend);
 Console.WriteLine("降排列后的List：");
 for (int i = 0; i < l.Count; i++)
 {
  Console.WriteLine(l[i].Key.ToString() + "\t:" + l[i].Value.ToString());
 }
 Console.ReadLine();
}

4.运行示例

希望本文所述对大家的C#程序设计有所帮助。