HybridDictionary.Item プロパティ
アセンブリ: System (system.dll 内)

Dim instance As HybridDictionary Dim key As Object Dim value As Object value = instance(key) instance(key) = value
public: virtual property Object^ default [Object^] { Object^ get (Object^ key) sealed; void set (Object^ key, Object^ value) sealed; }
/** @property */ public final Object get_Item (Object key) /** @property */ public final void set_Item (Object key, Object value)
プロパティ値
指定したキーに関連付けられている値。指定したキーが見つからない場合、そのキーを取得しようとした場合は null 参照 (Visual Basic では Nothing) が返され、そのキーを設定しようとした場合は、指定したキーを使用して新しいエントリが作成されます。


このプロパティでは、myCollection[key] という構文を使用して、コレクション内の特定の要素にアクセスできます。
Item プロパティを使用すると、HybridDictionary 内に存在しないキーの値を設定することで、新しい要素を追加することもできます (例 : myCollection["myNonexistentKey"] = myValue)。ただし、指定したキーが HybridDictionary 内に既に存在する場合、Item プロパティを設定すると既存の値が上書きされます。対照的に、Add メソッドは既存の要素を変更しません。
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。指定したキーが存在しないために返される null 参照 (Visual Basic では Nothing) と、指定したキーの値が null 参照 (Visual Basic では Nothing) であるために返される null 参照 (Visual Basic では Nothing) を区別するには、Contains メソッドを使用して、キーがリストに存在するかどうかを確認します。
このプロパティ値を取得することは、O(1) 操作になります。また、このプロパティを設定することも O(1) 操作になります。

HybridDictionary の要素を列挙するコード例を次に示します。
Imports System Imports System.Collections Imports System.Collections.Specialized Public Class SamplesHybridDictionary Public Shared Sub Main() ' Creates and initializes a new HybridDictionary. Dim myCol As New HybridDictionary() 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") myCol.Add("Plantain Bananas", "1.49") myCol.Add("Yellow Bananas", "0.79") myCol.Add("Strawberries", "3.33") myCol.Add("Cranberries", "5.98") myCol.Add("Navel Oranges", "1.29") myCol.Add("Grapes", "1.99") myCol.Add("Honeydew Melon", "0.59") myCol.Add("Seedless Watermelon", "0.49") myCol.Add("Pineapple", "1.49") myCol.Add("Nectarine", "1.99") myCol.Add("Plums", "1.69") myCol.Add("Peaches", "1.99") ' Display the contents of the collection using For Each. This is the preferred method. Console.WriteLine("Displays the elements using For Each:") PrintKeysAndValues1(myCol) ' Display the contents of the collection using the enumerator. Console.WriteLine("Displays the elements using the IDictionaryEnumerator:") 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) End Sub 'Main ' Uses the For Each statement which hides the complexity of the enumerator. ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection. Public Shared Sub PrintKeysAndValues1(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 ' Uses the enumerator. ' NOTE: The For Each statement is the preferred way of enumerating the contents of a collection. 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 ' Uses the Keys, Values, Count, and Item properties. Public Shared Sub PrintKeysAndValues3(myCol As HybridDictionary) 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 'SamplesHybridDictionary 'This code produces the following output. ' 'Displays the elements using For Each: ' KEY VALUE ' Seedless Watermelon 0.49 ' Nectarine 1.99 ' Cranberries 5.98 ' Plantain Bananas 1.49 ' Honeydew Melon 0.59 ' Pineapple 1.49 ' Strawberries 3.33 ' Grapes 1.99 ' Braeburn Apples 1.49 ' Peaches 1.99 ' Red Delicious Apples 0.99 ' Golden Delicious Apples 1.29 ' Yellow Bananas 0.79 ' Granny Smith Apples 0.89 ' Gala Apples 1.49 ' Plums 1.69 ' Navel Oranges 1.29 ' Fuji Apples 1.29 ' 'Displays the elements using the IDictionaryEnumerator: ' KEY VALUE ' Seedless Watermelon 0.49 ' Nectarine 1.99 ' Cranberries 5.98 ' Plantain Bananas 1.49 ' Honeydew Melon 0.59 ' Pineapple 1.49 ' Strawberries 3.33 ' Grapes 1.99 ' Braeburn Apples 1.49 ' Peaches 1.99 ' Red Delicious Apples 0.99 ' Golden Delicious Apples 1.29 ' Yellow Bananas 0.79 ' Granny Smith Apples 0.89 ' Gala Apples 1.49 ' Plums 1.69 ' Navel Oranges 1.29 ' Fuji Apples 1.29 ' 'Displays the elements using the Keys, Values, Count, and Item properties: ' INDEX KEY VALUE ' 0 Seedless Watermelon 0.49 ' 1 Nectarine 1.99 ' 2 Cranberries 5.98 ' 3 Plantain Bananas 1.49 ' 4 Honeydew Melon 0.59 ' 5 Pineapple 1.49 ' 6 Strawberries 3.33 ' 7 Grapes 1.99 ' 8 Braeburn Apples 1.49 ' 9 Peaches 1.99 ' 10 Red Delicious Apples 0.99 ' 11 Golden Delicious Apples 1.29 ' 12 Yellow Bananas 0.79 ' 13 Granny Smith Apples 0.89 ' 14 Gala Apples 1.49 ' 15 Plums 1.69 ' 16 Navel Oranges 1.29 ' 17 Fuji Apples 1.29
using System; using System.Collections; using System.Collections.Specialized; public class SamplesHybridDictionary { public static void Main() { // Creates and initializes a new HybridDictionary. HybridDictionary myCol = new HybridDictionary(); 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" ); myCol.Add( "Plantain Bananas", "1.49" ); myCol.Add( "Yellow Bananas", "0.79" ); myCol.Add( "Strawberries", "3.33" ); myCol.Add( "Cranberries", "5.98" ); myCol.Add( "Navel Oranges", "1.29" ); myCol.Add( "Grapes", "1.99" ); myCol.Add( "Honeydew Melon", "0.59" ); myCol.Add( "Seedless Watermelon", "0.49" ); myCol.Add( "Pineapple", "1.49" ); myCol.Add( "Nectarine", "1.99" ); myCol.Add( "Plums", "1.69" ); myCol.Add( "Peaches", "1.99" ); // 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 IDictionaryEnumerator:" ); 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 ); } // 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( IDictionary 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( IDictionary myCol ) { IDictionaryEnumerator myEnumerator = myCol.GetEnumerator(); Console.WriteLine( " KEY VALUE" ); while ( myEnumerator.MoveNext() ) Console.WriteLine( " {0,-25} {1}", myEnumerator.Key, myEnumerator.Value ); Console.WriteLine(); } // Uses the Keys, Values, Count, and Item properties. public static void PrintKeysAndValues3( HybridDictionary 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 Seedless Watermelon 0.49 Nectarine 1.99 Cranberries 5.98 Plantain Bananas 1.49 Honeydew Melon 0.59 Pineapple 1.49 Strawberries 3.33 Grapes 1.99 Braeburn Apples 1.49 Peaches 1.99 Red Delicious Apples 0.99 Golden Delicious Apples 1.29 Yellow Bananas 0.79 Granny Smith Apples 0.89 Gala Apples 1.49 Plums 1.69 Navel Oranges 1.29 Fuji Apples 1.29 Displays the elements using the IDictionaryEnumerator: KEY VALUE Seedless Watermelon 0.49 Nectarine 1.99 Cranberries 5.98 Plantain Bananas 1.49 Honeydew Melon 0.59 Pineapple 1.49 Strawberries 3.33 Grapes 1.99 Braeburn Apples 1.49 Peaches 1.99 Red Delicious Apples 0.99 Golden Delicious Apples 1.29 Yellow Bananas 0.79 Granny Smith Apples 0.89 Gala Apples 1.49 Plums 1.69 Navel Oranges 1.29 Fuji Apples 1.29 Displays the elements using the Keys, Values, Count, and Item properties: INDEX KEY VALUE 0 Seedless Watermelon 0.49 1 Nectarine 1.99 2 Cranberries 5.98 3 Plantain Bananas 1.49 4 Honeydew Melon 0.59 5 Pineapple 1.49 6 Strawberries 3.33 7 Grapes 1.99 8 Braeburn Apples 1.49 9 Peaches 1.99 10 Red Delicious Apples 0.99 11 Golden Delicious Apples 1.29 12 Yellow Bananas 0.79 13 Granny Smith Apples 0.89 14 Gala Apples 1.49 15 Plums 1.69 16 Navel Oranges 1.29 17 Fuji Apples 1.29 */
#using <System.dll> using namespace System; using namespace System::Collections; using namespace System::Collections::Specialized; void PrintKeysAndValues1( IDictionary^ myCol ); void PrintKeysAndValues2( IDictionary^ myCol ); void PrintKeysAndValues3( HybridDictionary^ myCol ); int main() { // Creates and initializes a new HybridDictionary. HybridDictionary^ myCol = gcnew HybridDictionary; 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" ); myCol->Add( "Plantain Bananas", "1.49" ); myCol->Add( "Yellow Bananas", "0.79" ); myCol->Add( "Strawberries", "3.33" ); myCol->Add( "Cranberries", "5.98" ); myCol->Add( "Navel Oranges", "1.29" ); myCol->Add( "Grapes", "1.99" ); myCol->Add( "Honeydew Melon", "0.59" ); myCol->Add( "Seedless Watermelon", "0.49" ); myCol->Add( "Pineapple", "1.49" ); myCol->Add( "Nectarine", "1.99" ); myCol->Add( "Plums", "1.69" ); myCol->Add( "Peaches", "1.99" ); // Display the contents of the collection using for each. This is the preferred method. Console::WriteLine( "Displays the elements using for each:" ); PrintKeysAndValues1( myCol ); // Display the contents of the collection using the enumerator. Console::WriteLine( "Displays the elements using the IDictionaryEnumerator:" ); 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 ); } // 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. void PrintKeysAndValues1( IDictionary^ myCol ) { Console::WriteLine( " KEY VALUE" ); for each ( DictionaryEntry^ de in myCol ) Console::WriteLine( " {0,-25} {1}", de->Key, de->Value ); Console::WriteLine(); } // Uses the enumerator. 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(); } // Uses the Keys, Values, Count, and Item properties. void PrintKeysAndValues3( HybridDictionary^ myCol ) { array<String^>^myKeys = gcnew array<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 for each: KEY VALUE Seedless Watermelon 0.49 Nectarine 1.99 Cranberries 5.98 Plantain Bananas 1.49 Honeydew Melon 0.59 Pineapple 1.49 Strawberries 3.33 Grapes 1.99 Braeburn Apples 1.49 Peaches 1.99 Red Delicious Apples 0.99 Golden Delicious Apples 1.29 Yellow Bananas 0.79 Granny Smith Apples 0.89 Gala Apples 1.49 Plums 1.69 Navel Oranges 1.29 Fuji Apples 1.29 Displays the elements using the IDictionaryEnumerator: KEY VALUE Seedless Watermelon 0.49 Nectarine 1.99 Cranberries 5.98 Plantain Bananas 1.49 Honeydew Melon 0.59 Pineapple 1.49 Strawberries 3.33 Grapes 1.99 Braeburn Apples 1.49 Peaches 1.99 Red Delicious Apples 0.99 Golden Delicious Apples 1.29 Yellow Bananas 0.79 Granny Smith Apples 0.89 Gala Apples 1.49 Plums 1.69 Navel Oranges 1.29 Fuji Apples 1.29 Displays the elements using the Keys, Values, Count, and Item properties: INDEX KEY VALUE 0 Seedless Watermelon 0.49 1 Nectarine 1.99 2 Cranberries 5.98 3 Plantain Bananas 1.49 4 Honeydew Melon 0.59 5 Pineapple 1.49 6 Strawberries 3.33 7 Grapes 1.99 8 Braeburn Apples 1.49 9 Peaches 1.99 10 Red Delicious Apples 0.99 11 Golden Delicious Apples 1.29 12 Yellow Bananas 0.79 13 Granny Smith Apples 0.89 14 Gala Apples 1.49 15 Plums 1.69 16 Navel Oranges 1.29 17 Fuji Apples 1.29 */
import System.*; import System.Collections.*; import System.Collections.Specialized.*; public class SamplesHybridDictionary { public static void main(String[] args) { // Creates and initializes a new HybridDictionary. HybridDictionary myCol = new HybridDictionary(); 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"); myCol.Add("Plantain Bananas", "1.49"); myCol.Add("Yellow Bananas", "0.79"); myCol.Add("Strawberries", "3.33"); myCol.Add("Cranberries", "5.98"); myCol.Add("Navel Oranges", "1.29"); myCol.Add("Grapes", "1.99"); myCol.Add("Honeydew Melon", "0.59"); myCol.Add("Seedless Watermelon", "0.49"); myCol.Add("Pineapple", "1.49"); myCol.Add("Nectarine", "1.99"); myCol.Add("Plums", "1.69"); myCol.Add("Peaches", "1.99"); // Display the contents of the collection using for. This is the // preferred method. Console.WriteLine("Displays the elements using for:"); PrintKeysAndValues1(myCol); // Display the contents of the collection using the enumerator. Console.WriteLine("Displays the elements using the" + " IDictionaryEnumerator:"); 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); } //main // Uses the for statement which hides the complexity of the enumerator. // NOTE: The for statement is the preferred way of enumerating the // contents of a collection. public static void PrintKeysAndValues1(IDictionary myCol) { String strKeys[] = new String[myCol.get_Count()]; myCol.get_Keys().CopyTo(strKeys,0); for (int iCtr=0; iCtr < myCol.get_Count(); iCtr++) { Console.WriteLine(" {0,-25} {1}", strKeys[iCtr], myCol.get_Item(strKeys[iCtr])); } Console.WriteLine(); } //PrintKeysAndValues1 // Uses the enumerator. // NOTE: The for statement is the preferred way of enumerating the // contents of a collection. public static void PrintKeysAndValues2(IDictionary myCol) { IDictionaryEnumerator myEnumerator = myCol.GetEnumerator(); Console.WriteLine(" KEY VALUE"); while(myEnumerator.MoveNext()) { Console.WriteLine(" {0,-25} {1}", myEnumerator.get_Key() , myEnumerator.get_Value()); } Console.WriteLine(); } //PrintKeysAndValues2 // Uses the Keys, Values, Count, and Item properties. public static void PrintKeysAndValues3(HybridDictionary myCol) { String myKeys[] = new String[myCol.get_Count()]; myCol.get_Keys().CopyTo(myKeys, 0); Console.WriteLine(" INDEX KEY VALUE"); for(int i=0; i < myCol.get_Count(); i++) { Console.WriteLine(" {0,-5} {1,-25} {2}", (Int32)i, myKeys[i], myCol.get_Item(myKeys[i])); } Console.WriteLine(); } //PrintKeysAndValues3 } //SamplesHybridDictionary /* Displays the elements using for: Strawberries 3.33 Yellow Bananas 0.79 Cranberries 5.98 Grapes 1.99 Granny Smith Apples 0.89 Seedless Watermelon 0.49 Honeydew Melon 0.59 Red Delicious Apples 0.99 Navel Oranges 1.29 Fuji Apples 1.29 Plantain Bananas 1.49 Gala Apples 1.49 Pineapple 1.49 Plums 1.69 Braeburn Apples 1.49 Peaches 1.99 Golden Delicious Apples 1.29 Nectarine 1.99 Displays the elements using the IDictionaryEnumerator: KEY VALUE Strawberries 3.33 Yellow Bananas 0.79 Cranberries 5.98 Grapes 1.99 Granny Smith Apples 0.89 Seedless Watermelon 0.49 Honeydew Melon 0.59 Red Delicious Apples 0.99 Navel Oranges 1.29 Fuji Apples 1.29 Plantain Bananas 1.49 Gala Apples 1.49 Pineapple 1.49 Plums 1.69 Braeburn Apples 1.49 Peaches 1.99 Golden Delicious Apples 1.29 Nectarine 1.99 Displays the elements using the Keys, Values, Count, and Item properties: INDEX KEY VALUE 0 Strawberries 3.33 1 Yellow Bananas 0.79 2 Cranberries 5.98 3 Grapes 1.99 4 Granny Smith Apples 0.89 5 Seedless Watermelon 0.49 6 Honeydew Melon 0.59 7 Red Delicious Apples 0.99 8 Navel Oranges 1.29 9 Fuji Apples 1.29 10 Plantain Bananas 1.49 11 Gala Apples 1.49 12 Pineapple 1.49 13 Plums 1.69 14 Braeburn Apples 1.49 15 Peaches 1.99 16 Golden Delicious Apples 1.29 17 Nectarine 1.99 */

Windows 98, Windows 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
開発プラットフォームの中には、.NET Framework によってサポートされていないバージョンがあります。サポートされているバージョンについては、「システム要件」を参照してください。


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