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; 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 */
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.