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。
dy("nrwz");
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