HybridDictionary::Keys Property
Gets an ICollection containing the keys in the HybridDictionary.
Assembly: System (in System.dll)
Property Value
Type: System.Collections::ICollectionAn ICollection containing the keys in the HybridDictionary.
Implements
IDictionary::KeysThe order of the values in the ICollection is unspecified, but it is the same order as the associated values in the ICollection returned by the Values method.
The returned ICollection is not a static copy; instead, the ICollection refers back to the keys in the original HybridDictionary. Therefore, changes to the HybridDictionary continue to be reflected in the ICollection.
Retrieving the value of this property is an O(1) operation.
The following code example enumerates the elements of a HybridDictionary.
#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 */
Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.