ListDictionary クラス
シングルリンク リストを使用して IDictionary を実装します。格納する項目数が通常 10 以下であるコレクションに対して推奨されます。
この型のすべてのメンバの一覧については、ListDictionary メンバ を参照してください。
System.Object
System.Collections.Specialized.ListDictionary
<Serializable>
Public Class ListDictionary Implements IDictionary, ICollection, IEnumerable
[C#]
[Serializable]
public class ListDictionary : IDictionary, ICollection, IEnumerable
[C++]
[Serializable]
public __gc class ListDictionary : public IDictionary, ICollection, IEnumerable
[JScript]
public
Serializable
class ListDictionary implements IDictionary, ICollection, IEnumerable
スレッドセーフ
この型の public static (Visual Basic では Shared) メンバは、マルチスレッド操作に対して安全です。インスタンス メンバがスレッド セーフになるかどうかは保証されていません。
この実装は、 ListDictionary 用の同期された (スレッド セーフな) ラッパーは提供しませんが、派生クラスでは、 SyncRoot プロパティを使用して、同期した ListDictionary を独自に作成できます。
コレクションの列挙処理は、本質的にはスレッド セーフな処理ではありません。コレクションが同期されている場合でも、他のスレッドがそのコレクションを変更する可能性はあり、そのような状況が発生すると列挙子は例外をスローします。列挙処理を確実にスレッド セーフに行うには、列挙中にコレクションをロックするか、他のスレッドによって行われた変更によってスローされる例外をキャッチします。
解説
これは、シングルリンク リストを使用した IDictionary の単純な実装です。要素数が 10 以下の場合は、この実装の方が Hashtable よりもサイズが小さく、処理が高速になります。多くの要素にとってパフォーマンスが重要である場合、この実装は使用しないでください。
Item 、 Add 、 Remove 、 Contains などのメンバは、 n が Count である O(n) 操作です。
キーには null 参照 (Visual Basic では Nothing) は使用できませんが、値には使用できます。
[Visual Basic, C#] C# 言語の foreach ステートメント (Visual Basic では for each) は、コレクション内の各要素の型を必要とします。 ListDictionary の各要素はキーと値の組み合わせであるため、要素の型は、キーの型や値の型にはなりません。その代わり、要素の型は DictionaryEntry になります。例:
foreach (DictionaryEntry myDE in myListDictionary) {...}
[Visual Basic]
Dim myDE As DictionaryEntry
For Each myDE In myListDictionary
...
Next myDE
[Visual Basic, C#] foreach ステートメントは、列挙子のラッパーです。これは、コレクションからの読み取りだけを許可し、コレクションへの書き込みを防ぎます。
使用例
[Visual Basic, C#, C++] ListDictionary のプロパティとメソッドのいくつかの例を次に示します。
Imports System
Imports System.Collections
Imports System.Collections.Specialized
Public Class SamplesListDictionary
Public Shared Sub Main()
' Creates and initializes a new ListDictionary.
Dim myCol As New ListDictionary()
myCol.Add("Braeburn Apples", "1.49")
myCol.Add("Fuji Apples", "1.29")
myCol.Add("Gala Apples", "1.49")
myCol.Add("Golden Delicious Apples", "1.29")
myCol.Add("Granny Smith Apples", "0.89")
myCol.Add("Red Delicious Apples", "0.99")
' Displays the values in the ListDictionary in three different ways.
Console.WriteLine("Displays the elements using for each:")
PrintKeysAndValues(myCol)
Console.WriteLine("Displays the elements using the IDictionaryEnumerator:")
PrintKeysAndValues2(myCol)
Console.WriteLine("Displays the elements using the Keys, Values, Count, and indexer properties:")
PrintKeysAndValues3(myCol)
' Copies the ListDictionary to an array with DictionaryEntry elements.
Dim myArr(myCol.Count) As DictionaryEntry
myCol.CopyTo(myArr, 0)
' Displays the values in the array.
Console.WriteLine("Displays the elements in the array:")
Console.WriteLine(" KEY VALUE")
Dim i As Integer
For i = 0 To myArr.Length - 1
Console.WriteLine(" {0,-25} {1}", myArr(i).Key, myArr(i).Value)
Next i
Console.WriteLine()
' Searches for a key.
If myCol.Contains("Kiwis") Then
Console.WriteLine("The collection contains the key ""Kiwis"".")
Else
Console.WriteLine("The collection does not contain the key ""Kiwis"".")
End If
Console.WriteLine()
' Deletes a key.
myCol.Remove("Plums")
Console.WriteLine("The collection contains the following elements after removing ""Plums"":")
PrintKeysAndValues(myCol)
' Clears the entire collection.
myCol.Clear()
Console.WriteLine("The collection contains the following elements after it is cleared:")
PrintKeysAndValues(myCol)
End Sub 'Main
Public Shared Sub PrintKeysAndValues(myCol As IDictionary)
Console.WriteLine(" KEY VALUE")
Dim de As DictionaryEntry
For Each de In myCol
Console.WriteLine(" {0,-25} {1}", de.Key, de.Value)
Next de
Console.WriteLine()
End Sub 'PrintKeysAndValues
Public Shared Sub PrintKeysAndValues2(myCol As IDictionary)
Dim myEnumerator As IDictionaryEnumerator = myCol.GetEnumerator()
Console.WriteLine(" KEY VALUE")
While myEnumerator.MoveNext()
Console.WriteLine(" {0,-25} {1}", myEnumerator.Key, myEnumerator.Value)
End While
Console.WriteLine()
End Sub 'PrintKeysAndValues2
Public Shared Sub PrintKeysAndValues3(myCol As ListDictionary)
Dim myKeys(myCol.Count) As [String]
myCol.Keys.CopyTo(myKeys, 0)
Console.WriteLine(" INDEX KEY VALUE")
Dim i As Integer
For i = 0 To myCol.Count - 1
Console.WriteLine(" {0,-5} {1,-25} {2}", i, myKeys(i), myCol(myKeys(i)))
Next i
Console.WriteLine()
End Sub 'PrintKeysAndValues3
End Class 'SamplesListDictionary
'This code produces the following output.
'
'Displays the elements using for each:
' KEY VALUE
' Braeburn Apples 1.49
' Fuji Apples 1.29
' Gala Apples 1.49
' Golden Delicious Apples 1.29
' Granny Smith Apples 0.89
' Red Delicious Apples 0.99
'
'Displays the elements using the IDictionaryEnumerator:
' KEY VALUE
' Braeburn Apples 1.49
' Fuji Apples 1.29
' Gala Apples 1.49
' Golden Delicious Apples 1.29
' Granny Smith Apples 0.89
' Red Delicious Apples 0.99
'
'Displays the elements using the Keys, Values, Count, and indexer properties:
' INDEX KEY VALUE
' 0 Braeburn Apples 1.49
' 1 Fuji Apples 1.29
' 2 Gala Apples 1.49
' 3 Golden Delicious Apples 1.29
' 4 Granny Smith Apples 0.89
' 5 Red Delicious Apples 0.99
'
'Displays the elements in the array:
' KEY VALUE
' Braeburn Apples 1.49
' Fuji Apples 1.29
' Gala Apples 1.49
' Golden Delicious Apples 1.29
' Granny Smith Apples 0.89
' Red Delicious Apples 0.99
'
'The collection does not contain the key "Kiwis".
'
'The collection contains the following elements after removing "Plums":
' KEY VALUE
' Braeburn Apples 1.49
' Fuji Apples 1.29
' Gala Apples 1.49
' Golden Delicious Apples 1.29
' Granny Smith Apples 0.89
' Red Delicious Apples 0.99
'
'The collection contains the following elements after it is cleared:
' KEY VALUE
'
[C#]
using System;
using System.Collections;
using System.Collections.Specialized;
public class SamplesListDictionary {
public static void Main() {
// Creates and initializes a new ListDictionary.
ListDictionary myCol = new ListDictionary();
myCol.Add( "Braeburn Apples", "1.49" );
myCol.Add( "Fuji Apples", "1.29" );
myCol.Add( "Gala Apples", "1.49" );
myCol.Add( "Golden Delicious Apples", "1.29" );
myCol.Add( "Granny Smith Apples", "0.89" );
myCol.Add( "Red Delicious Apples", "0.99" );
// Displays the values in the ListDictionary in three different ways.
Console.WriteLine( "Displays the elements using foreach:" );
PrintKeysAndValues( myCol );
Console.WriteLine( "Displays the elements using the IDictionaryEnumerator:" );
PrintKeysAndValues2( myCol );
Console.WriteLine( "Displays the elements using the Keys, Values, Count, and indexer properties:" );
PrintKeysAndValues3( myCol );
// Copies the ListDictionary 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,-25} {1}", myArr[i].Key, myArr[i].Value );
Console.WriteLine();
// Searches for a key.
if ( myCol.Contains( "Kiwis" ) )
Console.WriteLine( "The collection contains the key \"Kiwis\"." );
else
Console.WriteLine( "The collection does not contain the key \"Kiwis\"." );
Console.WriteLine();
// Deletes a key.
myCol.Remove( "Plums" );
Console.WriteLine( "The collection contains the following elements after removing \"Plums\":" );
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( IDictionary myCol ) {
Console.WriteLine( " KEY VALUE" );
foreach ( DictionaryEntry de in myCol )
Console.WriteLine( " {0,-25} {1}", de.Key, de.Value );
Console.WriteLine();
}
public static void PrintKeysAndValues2( IDictionary myCol ) {
IDictionaryEnumerator myEnumerator = myCol.GetEnumerator();
Console.WriteLine( " KEY VALUE" );
while ( myEnumerator.MoveNext() )
Console.WriteLine( " {0,-25} {1}", myEnumerator.Key, myEnumerator.Value );
Console.WriteLine();
}
public static void PrintKeysAndValues3( ListDictionary 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
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
Displays the elements using the IDictionaryEnumerator:
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
Displays the elements using the Keys, Values, Count, and indexer properties:
INDEX KEY VALUE
0 Braeburn Apples 1.49
1 Fuji Apples 1.29
2 Gala Apples 1.49
3 Golden Delicious Apples 1.29
4 Granny Smith Apples 0.89
5 Red Delicious Apples 0.99
Displays the elements in the array:
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
The collection does not contain the key "Kiwis".
The collection contains the following elements after removing "Plums":
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
The collection contains the following elements after it is cleared:
KEY VALUE
*/
[C++]
#using <mscorlib.dll>
#using <System.dll>
using namespace System;
using namespace System::Collections;
using namespace System::Collections::Specialized;
void PrintKeysAndValues( IDictionary* myCol ) {
Console::WriteLine( S" KEY VALUE" );
IEnumerator* myEnum = myCol->GetEnumerator();
while (myEnum->MoveNext())
{
DictionaryEntry de = *__try_cast<DictionaryEntry*>(myEnum->Current);
Console::WriteLine( S" {0,-25} {1}", de.Key, de.Value );
}
Console::WriteLine();
}
void PrintKeysAndValues2( IDictionary* myCol ) {
IDictionaryEnumerator* myEnumerator = myCol->GetEnumerator();
Console::WriteLine( S" KEY VALUE" );
while ( myEnumerator->MoveNext() )
Console::WriteLine( S" {0,-25} {1}", myEnumerator->Key, myEnumerator->Value );
Console::WriteLine();
}
void PrintKeysAndValues3( ListDictionary* myCol ) {
String* myKeys[] = new String*[myCol->Count];
myCol->Keys->CopyTo( myKeys, 0 );
Console::WriteLine( S" INDEX KEY VALUE" );
for ( int i = 0; i < myCol->Count; i++ )
Console::WriteLine( S" {0,-5} {1,-25} {2}", __box(i), myKeys->Item[i], myCol->Item[myKeys[i]] );
Console::WriteLine();
}
int main() {
// Creates and initializes a new ListDictionary.
ListDictionary* myCol = new ListDictionary();
myCol->Add( S"Braeburn Apples", S"1.49" );
myCol->Add( S"Fuji Apples", S"1.29" );
myCol->Add( S"Gala Apples", S"1.49" );
myCol->Add( S"Golden Delicious Apples", S"1.29" );
myCol->Add( S"Granny Smith Apples", S"0.89" );
myCol->Add( S"Red Delicious Apples", S"0.99" );
// Displays the values in the ListDictionary in three different ways.
Console::WriteLine( S"Displays the elements using foreach:" );
PrintKeysAndValues( myCol );
Console::WriteLine( S"Displays the elements using the IDictionaryEnumerator:" );
PrintKeysAndValues2( myCol );
Console::WriteLine( S"Displays the elements using the Keys, Values, Count, and indexer properties:" );
PrintKeysAndValues3( myCol );
// Copies the ListDictionary to an array with DictionaryEntry elements.
DictionaryEntry myArr[] = new DictionaryEntry[myCol->Count];
myCol->CopyTo( myArr, 0 );
// Displays the values in the array.
Console::WriteLine( S"Displays the elements in the array:" );
Console::WriteLine( S" KEY VALUE" );
for ( int i = 0; i < myArr->Length; i++ )
Console::WriteLine( S" {0,-25} {1}", myArr[i].Key, myArr[i].Value );
Console::WriteLine();
// Searches for a key.
if ( myCol->Contains( S"Kiwis" ) )
Console::WriteLine( S"The collection contains the key \"Kiwis\"." );
else
Console::WriteLine( S"The collection does not contain the key \"Kiwis\"." );
Console::WriteLine();
// Deletes a key.
myCol->Remove( S"Plums" );
Console::WriteLine( S"The collection contains the following elements after removing \"Plums\":" );
PrintKeysAndValues( myCol );
// Clears the entire collection.
myCol->Clear();
Console::WriteLine( S"The collection contains the following elements after it is cleared:" );
PrintKeysAndValues( myCol );
}
/*
This code produces the following output.
Displays the elements using foreach:
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
Displays the elements using the IDictionaryEnumerator:
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
Displays the elements using the Keys, Values, Count, and indexer properties:
INDEX KEY VALUE
0 Braeburn Apples 1.49
1 Fuji Apples 1.29
2 Gala Apples 1.49
3 Golden Delicious Apples 1.29
4 Granny Smith Apples 0.89
5 Red Delicious Apples 0.99
Displays the elements in the array:
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
The collection does not contain the key "Kiwis".
The collection contains the following elements after removing "Plums":
KEY VALUE
Braeburn Apples 1.49
Fuji Apples 1.29
Gala Apples 1.49
Golden Delicious Apples 1.29
Granny Smith Apples 0.89
Red Delicious Apples 0.99
The collection contains the following elements after it is cleared:
KEY VALUE
*/
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をクリックします。
必要条件
名前空間: System.Collections.Specialized
プラットフォーム: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 ファミリ, .NET Compact Framework - Windows CE .NET
アセンブリ: System (System.dll 内)
参照
ListDictionary メンバ | System.Collections.Specialized 名前空間 | IDictionary | Hashtable | カルチャを認識しない文字列操作の実行