看下，怎么对哈希表排序，就明白了
对哈希表进行排序
对哈希表进行排序在这里的定义是对key/键值对中的key按一定规则重新排列，但是实际上这个定义是不能实现的，因为我们无法直接在Hashtable进行对key进行重新排列，如果需要Hashtable提供某种规则的输出，可以采用一种变通的做法：
ArrayList akeys=new ArrayList(ht.Keys); //别忘了导入System.Collections
akeys.Sort(); //按字母顺序进行排序
foreach(string skey in akeys)
{
Console.Write(skey ":");
Console.WriteLine(ht[skey]);//排序后输出
}
注意：用foreach
下面是一个简单的例子:
class SampleHashtable
{
/// <summary>
/// The main entry point for the application.
/// </summary>
[STAThread]
static void Main(string[] args)
{
// Create and initialize a new Hashtable.
Hashtable table = new Hashtable();
//Student Name, Grade
table.Add("leiwanjun", 100);
table.Add("wanghuan", 87);
table.Add("wuhailong", 92);
table.Add("renyao", 76);
table.Add("tanghonglei", 84);
table.Add("chenxiaoping", 91);
table.Add("liupeixun", 80);
table.Add("huyoumou", 87);
// Display the properties and values of the Hashtable.
Console.WriteLine("Count: {0}", table.Count);
PrintTable(table);
Console.WriteLine();
int g = (int) table["wuhailong"];
Console.WriteLine ("wuhailong's grade is: {0}", g);
Console.WriteLine();
PrintItems ("All Names", table.Keys);
Console.WriteLine();
PrintItems ("All Grades", table.Values);
}
public static void PrintTable( Hashtable myList)
{
Console.WriteLine ("{0, -15} {1, -15}", "Name","Grade");
Console.WriteLine ("{0, -15} {1, -15}", "----","-----");
// // 排序
// ArrayList al = new ArrayList(myList.Keys);
// al.Sort();
// foreach (string Name in al)
// {
// Console.WriteLine("{0, -15} {1, -15}", Name, myList[Name]);
// }
// //
//遍历哈希表中的每个元素,直接输出
foreach (DictionaryEntry e in myList)
{
Console.WriteLine ("{0, -15} {1, -15}", e.Key, e.Value);
}
}
public static void PrintItems(string title, IEnumerable myList )
{
Console.Write ("{0}: ", title);
StringBuilder sb = new StringBuilder();
foreach (object o in myList)
{
sb.AppendFormat( "{0}, ", o);
}
sb.Remove(sb.Length - 2, 2);
Console.WriteLine(sb);
