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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;
}
}
}
</div>
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