C#中怎么做到这样的stylevar["charset"]下标为字符串的数组？

C#中怎么做到这样的stylevar["charset"]下标为字符串的数组？
本文来自: 站长(http://www.qqcf.com) 详细出处参考：http://study.qqcf.com/web/721/268745.htm

问：
在PHP中数组下标可以是字符串，比如：stylevar["charset"]
这样的好处是非常便于记忆，不容易出错。请问在C#中怎么用这样的数据表示方法，谢谢！
______________________________________________________________________________________________
答1：
用索引器
______________________________________________________________________________________________
答2：
namespace Programming_CSharp
{
using System;

// a simplified ListBox control
public class ListBoxTest
{
// initialize the list box with strings
public ListBoxTest(params string[] initialStrings)
{
// allocate space for the strings
strings = new String[256];

// copy the strings passed in to the constructor
foreach (string s in initialStrings)
{
strings[ctr++] = s;
}
}

// add a single string to the end of the list box
public void Add(string theString)
{
strings[ctr] = theString;
ctr++;
}

// allow array-like access
public string this[int index]
{
get
{
if (index < 0 || index >= strings.Length)
{
// handle bad index
}
return strings[index];
}
set
{
strings[index] = value;
}
}

private int findString(string searchString)
{
for (int i = 0;i<strings.Length;i++)
{
if (strings[i].StartsWith(searchString))
{
return i;
}
}
return -1;
}
// index on string
public string this[string index]
{
get
{
if (index.Length == 0)
{
// handle bad index
}

return this[findString(index)];
}
set
{
strings[findString(index)] = value;
}
}

// publish how many strings you hold
public int GetNumEntries()
{
return ctr;
}

private string[] strings;
private int ctr = 0;
}

public class Tester
{
static void Main()
{
// create a new list box and initialize
ListBoxTest lbt =
new ListBoxTest("Hello", "World");

// add a few strings
lbt.Add("Who");
lbt.Add("Is");
lbt.Add("John");
lbt.Add("Galt");

// test the access
string subst = "Universe";
lbt[1] = subst;
lbt["Hel"] = "GoodBye";
// lbt["xyz"] = "oops";

// access all the strings
for (int i = 0;i<lbt.GetNumEntries();i++)
{
Console.WriteLine("lbt[{0}]: {1}",i,lbt[i]);
} // end for
} // end main
} // end tester
} // end namespace