Hashtable
Hashtable class represents a collection of key-and-value pairs that are organized based on the hash code of the key. It uses the key to access the elements in the collection.
Some of the commonly used methods in Hashtable class are −
| Sr.No. | Method & Description |
|---|---|
| 1 |
public virtual void Add(object key, object value); Adds an element with the specified key and value into the Hashtable. |
| 2 |
public virtual void Clear(); Removes all elements from the Hashtable. |
| 3 |
public virtual bool ContainsKey(object key); Determines whether the Hashtable contains a specific key. |
| 4 |
public virtual bool ContainsValue(object value); Determines whether the Hashtable contains a specific value. |
The following is an example showing the usage of Hashtable class in C# −
Example
Live Demo
using System;
using System.Collections;
namespace Demo {
class Program {
static void Main(string[] args) {
Hashtable ht = new Hashtable();
ht.Add("D01", "Finance");
ht.Add("D02", "HR");
ht.Add("D03", "Operations");
if (ht.ContainsValue("Marketing")) {
Console.WriteLine("This department name is already in the list");
} else {
ht.Add("D04", "Marketing");
}
ICollection key = ht.Keys;
foreach (string k in key) {
Console.WriteLine(k + ": " + ht[k]);
}
Console.ReadKey();
}
}
}输出
D04: Marketing D02: HR D03: Operations D01: Finance
字典
字典是C#中的键值对集合。Dictionary
以下是一些方法：
| 序号 | 方法及描述 |
|---|---|
| 1 |
Add 在字典中添加键值对 
迦恩计算机资源网源码(图书销售类)
下载
采用三层架构开发，前台集成了产品在线展示，用户注册、在线调查、在线投稿后台有类别管理\图书管理\订单管理\会员管理\配送范围管理\邮件列表\广告管理\友情链接管理等后台添加图书时自动生成缩略图和文字水印主要参考了petshop的设计架构、使用了Asp.net2.0中很多MemberShip、master等新功能后台管理地址/web/admin/ 超级管理员账号密码均为aspx1特别提示：该系统需要 |
| 2 |
Clear() 移除所有的键和值 |
| 3 |
Remove 移除指定键的元素 |
| 4 |
ContainsKey 检查字典中是否存在指定的键 |
| 5 |
ContainsValue 检查字典中是否存在指定的键值 |
| 6 |
Count 计算键值对的数量 |
| 7 |
Clear 从字典中移除所有元素 |
让我们看看如何向字典中添加元素并显示数量：
示例
using System;
using System.Collections.Generic;
public class Demo {
public static void Main() {
IDictionary d = new Dictionary ();
d.Add(1,44);
d.Add(2,34);
d.Add(3,66);
d.Add(4,47);
d.Add(5,76);
Console.WriteLine(d.Count);
}
} 
