C# 0 The Complete Reference

DictionaryEntry

structure, but you will usually access the keys and values individually using the methods 

and properties defined by 

SortedList

.

The following program demonstrates 

SortedList

. It reworks and expands the 

Hashtable

demonstration program from the previous section, substituting 

SortedList

. When you 

examine the output, you will see that the 

SortedList

 version is sorted by key.

// Demonstrate a SortedList.

using System;

using System.Collections;

Method

Description

public vir tual bool ContainsKey(object 

k

)

Returns true if 

k

 is a key in the invoking 

SortedList

.

Returns false other wise.

public vir tual bool ContainsValue(object 

v

)

Returns true if 

v

 is a value in the invoking 

SortedList

.

Returns false other wise.

public vir tual object GetByIndex(int 

idx

)

Returns the value at the index specified by 

idx.

public vir tual IDictionar yEnumerator

    GetEnumerator( )

Returns an 

IDictionaryEnumerator

 for the invoking 

SortedList

.

public vir tual object GetKey(int 

idx

)

Returns the value of the key at the index specified by 

idx.

public vir tual IList GetKeyList( )

Returns an 

IList

 collection of the keys in the invoking 

SortedList

.

public vir tual IList GetValueList( )

Returns an 

IList

 collection of the values in the invoking 

SortedList

.

public vir tual int IndexOfKey(object 

k

)

Returns the index of the key specified by 

k.

 Returns –1 

if the key is not in the list.

public vir tual int IndexOfValue(object 

v

)

Returns the index of the first occurrence of the value 

specified by 

v.

 Returns –1 if the value is not in the list.

public vir tual void

     SetByIndex(int 

idx

, object 

v

)

Sets the value at the index specified by 

idx

 to the value 

passed in 

v.

public static Sor tedList

    Synchronized(Sor tedList 

sl

)

Returns a synchronized version of the 

SortedList

passed in 

sl.

public vir tual void TrimToSize( )

Sets 

Capacity

 to 

Count

.

T

ABLE

 24-6 

Several Commonly Used Methods Defi ned by 

SortedList

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class SLDemo {

  static void Main() {

    // Create a sorted SortedList.

    SortedList sl = new SortedList();

    // Add elements to the table.

    sl.Add("house", "Dwelling");

    sl.Add("car", "Means of transport");

    sl.Add("book", "Collection of printed words");

    sl.Add("apple", "Edible fruit");

    // Can also add by using the indexer.

    sl["tractor"] = "Farm implement";

    // Get a collection of the keys.

    ICollection c = sl.Keys;

    // Use the keys to obtain the values.

    Console.WriteLine("Contents of list via indexer.");

    foreach(string str in c)

      Console.WriteLine(str + ": " + sl[str]);

    Console.WriteLine();

    // Display list using integer indexes.

    Console.WriteLine("Contents by integer indexes.");

    for(int i=0; i < sl.Count; i++)

      Console.WriteLine(sl.GetByIndex(i));

    Console.WriteLine();

    // Show integer indexes of entries.

    Console.WriteLine("Integer indexes of entries.");

    foreach(string str in c)

      Console.WriteLine(str + ": " + sl.IndexOfKey(str));

  }

}

The output is shown here:

Contents of list via indexer.

apple: Edible fruit

book: Collection of printed words

car: Means of transport

house: Dwelling

tractor: Farm implement

Contents by integer indexes.

Edible fruit

Collection of printed words

Means of transport

Dwelling

Farm implement

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