StringDictionary Class

1. key與value均為string型態.
2. 不維持排序.
3. Key值預設不區分大小寫. (先轉為小寫再存取元素).

Example

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

public class SamplesStringDictionary {

public static void Main() {

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

// Display the contents of the collection using foreach. This is the preferred method.
Console.WriteLine( "Displays the elements using foreach:" );
PrintKeysAndValues1( myCol );

// Display the contents of the collection using the enumerator.
Console.WriteLine( "Displays the elements using the IEnumerator:" );
PrintKeysAndValues2( myCol );

// Display the contents of the collection using the Keys, Values, Count, and Item properties.
Console.WriteLine( "Displays the elements using the Keys, Values, Count, and Item properties:" );
PrintKeysAndValues3( myCol );

// Copies the StringDictionary to an array with DictionaryEntry elements.
DictionaryEntry[] myArr = new DictionaryEntry[myCol.Count];
myCol.CopyTo( myArr, 0 );

// Displays the values in the array.
Console.WriteLine( "Displays the elements in the array:" );
Console.WriteLine( " KEY VALUE" );
for ( int i = 0; i < myArr.Length; i++ )
Console.WriteLine( " {0,-10} {1}", myArr[i].Key, myArr[i].Value );
Console.WriteLine();

// Searches for a value.
if ( myCol.ContainsValue( "amarillo" ) )
Console.WriteLine( "The collection contains the value \"amarillo\"." );
else
Console.WriteLine( "The collection does not contain the value \"amarillo\"." );
Console.WriteLine();

// Searches for a key and deletes it.
if ( myCol.ContainsKey( "green" ) )
myCol.Remove( "green" );
Console.WriteLine( "The collection contains the following elements after removing \"green\":" );
PrintKeysAndValues1( myCol );

// Clears the entire collection.
myCol.Clear();
Console.WriteLine( "The collection contains the following elements after it is cleared:" );
PrintKeysAndValues1( myCol );

}

// Uses the foreach statement which hides the complexity of the enumerator.
// NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
public static void PrintKeysAndValues1( StringDictionary myCol ) {
Console.WriteLine( " KEY VALUE" );
foreach ( DictionaryEntry de in myCol )
Console.WriteLine( " {0,-25} {1}", de.Key, de.Value );
Console.WriteLine();
}

// Uses the enumerator. 
// NOTE: The foreach statement is the preferred way of enumerating the contents of a collection.
public static void PrintKeysAndValues2( StringDictionary myCol ) {
IEnumerator myEnumerator = myCol.GetEnumerator();
DictionaryEntry de;
Console.WriteLine( " KEY VALUE" );
while ( myEnumerator.MoveNext() ) {
de = (DictionaryEntry) myEnumerator.Current;
Console.WriteLine( " {0,-25} {1}", de.Key, de.Value );
}
Console.WriteLine();
}

// Uses the Keys, Values, Count, and Item properties.
public static void PrintKeysAndValues3( StringDictionary myCol ) {
String[] myKeys = new String[myCol.Count];
myCol.Keys.CopyTo( myKeys, 0 );

Console.WriteLine( " INDEX KEY VALUE" );
for ( int i = 0; i < myCol.Count; i++ )
Console.WriteLine( " {0,-5} {1,-25} {2}", i, myKeys[i], myCol[myKeys[i]] );
Console.WriteLine();
}

}

/*
This code produces the following output.

Displays the elements using foreach:
KEY VALUE
red rojo
blue azul
green verde

Displays the elements using the IEnumerator:
KEY VALUE
red rojo
blue azul
green verde

Displays the elements using the Keys, Values, Count, and Item properties:
INDEX KEY VALUE
0 red rojo
1 blue azul
2 green verde

Displays the elements in the array:
KEY VALUE
red rojo
blue azul
green verde

The collection does not contain the value "amarillo".

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

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

*/