案例:
NameValueCollection nameValueCollection = Request.Params;//获得连接地址中的所有参数
//获取各个参数,eg:
var a = nameValueCollection.Get("ID");
var name = nameValueCollection.Get("Name");
1.NameValueCollection类集合是基于 NameObjectCollectionBase 类。
但与 NameObjectCollectionBase 不同,该类在一个键下存储多个字符串值(就是键相同,值就连接起来如下例子)。该类可用于标头、查询字符串和窗体数据。
每个元素都是一个键/值对。NameValueCollection 的容量是 NameValueCollection 可以保存的元素数。
NameValueCollection 的默认初始容量为零。随着向 NameValueCollection 中添加元素,容量通过重新分配按需自动增加。
如下例子:
- 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");
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.
- Hashtable ht = new Hashtable();
- ht.Add("key","value");
- ht.Add("key", "value1"); //出错
- ht["key"] = "value1"; //正确
3.初始化NameValueCollection
初始化NameValueCollection需引用using System.Collections.Specialized;
完整例子源码:
- using System; using System.Collections;
- using System.Collections.Specialized;
- namespace SamplesNameValueCollection
- {
- class Program
- {
- public static void Main()
- {
- //初始化NameValueCollection需引用using System.Collections.Specialized;
- 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");
- // Displays the values in the NameValueCollection in two different ways.
- //显示键,值
- Console.WriteLine("Displays the elements using the AllKeys property and the Item (indexer) property:");
- PrintKeysAndValues(myCol);
- Console.WriteLine("Displays the elements using GetKey and Get:");
- PrintKeysAndValues2(myCol);
- // Gets a value either by index or by key.
- //按索引或值获取
- Console.WriteLine("Index 1 contains the value {0}.", myCol[1]);//索引1的值
- Console.WriteLine("Key /"red/" has the value {0}.", myCol["red"]);//键为red的对应值rouge
- Console.WriteLine();
- // Copies the values to a string array and displays the string array.
- String[] myStrArr = new String[myCol.Count];
- myCol.CopyTo(myStrArr, 0);
- Console.WriteLine("The string array contains:");
- foreach (String s in myStrArr)
- Console.WriteLine(" {0}", s);
- Console.WriteLine();
- //查找green键值然后删除
- myCol.Remove("green");
- Console.WriteLine("The collection contains the following elements after removing /"green/":");
- PrintKeysAndValues(myCol);
- //清空集合
- myCol.Clear();
- Console.WriteLine("The collection contains the following elements after it is cleared:");
- PrintKeysAndValues(myCol);
- }
- //显示键,值
- public static void PrintKeysAndValues(NameValueCollection myCol)
- {
- IEnumerator myEnumerator = myCol.GetEnumerator();
- Console.WriteLine(" KEY VALUE");
- foreach (String s in myCol.AllKeys)
- Console.WriteLine(" {0,-10} {1}", s, myCol[s]);
- Console.WriteLine();
- }
- //显示索引, 键,值
- public static void PrintKeysAndValues2(NameValueCollection myCol)
- {
- Console.WriteLine(" [INDEX] KEY VALUE");
- for (int i = 0; i < myCol.Count; i++)
- Console.WriteLine(" [{0}] {1,-10} {2}", i, myCol.GetKey(i), myCol.Get(i));
- Console.WriteLine();
- }
- }
- }
4.NameValueCollection遍历
与Hashtable相似:
- 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["red"] = "dd";
- foreach (string key in myCol.Keys)
- {
- Console.WriteLine("{0}:{1}", key, myCol[key]);
- }
- Console.ReadLine();