NameValueCollection Class

1. 以NameObjectCollectionBase為基礎的物件. 同一個Key可以存放多組的字串. 適用於headers, query string and form data.
2. 元素為key/value pair.
3. 不維持排序.
4. Key值以雜湊值存取. 預設不分大小寫.
5. Key跟Value都可以為null.

Example

using System;
using System.Collections;
using System.Collections.Specialized;

public class SamplesNameValueCollection {

public static void Main() {

// Creates and initializes a new NameValueCollection.
NameValueCollection myCol = new NameValueCollection();
myCol.Add( "red", "rojo" );
myCol.Add( "green", "verde" );
myCol.Add( "blue", "azul" );
myCol.Add( "red", "rouge" );

// Displays the values in the NameValueCollection in two different ways.
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.
Console.WriteLine( "Index 1 contains the value {0}.", myCol[1] );
Console.WriteLine( "Key \"red\" has the value {0}.", myCol["red"] );
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();

// Searches for a key and deletes it.
myCol.Remove( "green" );
Console.WriteLine( "The collection contains the following elements after removing \"green\":" );
PrintKeysAndValues( myCol );

// Clears the entire collection.
myCol.Clear();
Console.WriteLine( "The collection contains the following elements after it is cleared:" );
PrintKeysAndValues( myCol );

}

public static void PrintKeysAndValues( NameValueCollection myCol ) {
Console.WriteLine( " KEY VALUE" );
foreach ( String s in myCol.AllKeys )
Console.WriteLine( " {0,-10} {1}", s, myCol[s] );
Console.WriteLine();
}

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();
}


}

/*

This code produces the following output.

Displays the elements using the AllKeys property and the Item (indexer) property:
KEY VALUE
red rojo,rouge
green verde
blue azul

Displays the elements using GetKey and Get:
[INDEX] KEY VALUE
[0] red rojo,rouge
[1] green verde
[2] blue azul

Index 1 contains the value verde.
Key "red" has the value rojo,rouge.

The string array contains:
rojo,rouge
verde
azul

The collection contains the following elements after removing "green":
KEY VALUE
red rojo,rouge
blue azul

The collection contains the following elements after it is cleared:
KEY VALUE


*/