在做一个项目的过程中,需要将一些数据组织起来,第一个想到的就是HashTable,

主要就是考虑它用得比较广,再然后是KEY的唯一性,于是乎就用了。用了之后就发现了后果很严重：数据加入哈希表的时候的顺序和迭代输出的顺序不一致，这问题可真严重了，既然哈希表不能满足要求，只能用其它的数据结构了，找了一下就NameValueCollection了，用起来来还真好，主是没有支持KEY的唯一性，不可无所谓了，反正我这个项目也不好要求其唯一性了。

关于HashTable和NameValueCollection输出顺序对比可通过以下示例得出。

using System;

using System.Collections.Generic;

using System.Collections;

using System.Collections.Specialized;

public class MyClass

{

public static void Main()

{

System.Collections.Hashtable ht = new System.Collections.Hashtable ();

ht.Add ( "DdpMDisplaySeq".Trim ( ) , "Display Sequence".Trim ( ) );

ht.Add ( "DdpMNameChi".Trim ( ) , "Name (Chinese)".Trim ( ) );

ht.Add ( "DdpMNameEng".Trim ( ) , "Name (English)".Trim ( ) );

ht.Add ( "Comment".Trim ( ) , "Comment".Trim ( ) );

ht.Add ( "DdpMMarketCode".Trim ( ) , "Market Code".Trim ( ) );

foreach ( object key in ht.Keys )

{

Console.WriteLine( "{0} {1} {2},{3}" , key , ht[key] , key.GetHashCode() , ht[key].GetHashCode() );

}

NameValueCollection myCol = new NameValueCollection();

myCol.Add ( "DdpMDisplaySeq".Trim ( ) , "Display Sequence".Trim ( ) );

myCol.Add ( "DdpMNameChi".Trim ( ) , "Name (Chinese)".Trim ( ) );

myCol.Add ( "DdpMNameEng".Trim ( ) , "Name (English)".Trim ( ) );

myCol.Add ( "Comment".Trim ( ) , "Comment".Trim ( ) );

myCol.Add ( "DdpMMarketCode".Trim ( ) , "Market Code".Trim ( ) );

foreach ( string key in myCol.Keys )

{

Console.WriteLine( "{0}/{1}" , key , myCol[key] );

}

RL();

}

Helper methods#region Helper methods

private static void WL(object text, params object[] args)

{

Console.WriteLine(text.ToString(), args);

}

private static void RL()

{

Console.ReadLine();

}

private static void Break()

{

System.Diagnostics.Debugger.Break();

}

#endregion

}

输出结果为:

DdpMDisplaySeq Display Sequence -1989459343,1288318213

DdpMMarketCode Market Code 1652325269,-2031292722

DdpMNameChi Name (Chinese) -408135670,-703205071

DdpMNameEng Name (English) -1570541874,-1899340382

Comment Comment -498702589,-498702589

DdpMDisplaySeq/Display Sequence

DdpMNameChi/Name (Chinese)

DdpMNameEng/Name (English)

Comment/Comment

DdpMMarketCode/Market Code

2.NameValueCollection与Hashtable的区别

a.引用区别

hashtable:using System.Collections;

NameValueCollection:using System.Collections.Specialized;

b.键是否重复

NameValueCollection:允许重复.

HashTable是键-值集合,但键不能出现重复.

NameValueCollection myCol = new NameValueCollection();

myCol.Add("red", "rojo");//如果键值red相同结果合并 rojo,rouge

myCol.Add("green", "verde");

myCol.Add("blue", "azul");

myCol.Add("red", "rouge");