NameObjectCollectionBase.BaseGetKey Method (Int32)
.NET Framework (current version)
Gets the key of the entry at the specified index of the NameObjectCollectionBase instance.
Assembly: System (in System.dll)
Parameters
- index
-
Type:
System.Int32
The zero-based index of the key to get.
Return Value
Type: System.StringA String that represents the key of the entry at the specified index.
| Exception | Condition |
|---|---|
| ArgumentOutOfRangeException | index is outside the valid range of indexes for the collection. |
This method is an O(1) operation.
The following code example uses BaseGetKey and BaseGet to get specific keys and values.
using System; using System.Collections; using System.Collections.Specialized; public class MyCollection : NameObjectCollectionBase { private DictionaryEntry _de = new DictionaryEntry(); // Gets a key-and-value pair (DictionaryEntry) using an index. public DictionaryEntry this[ int index ] { get { _de.Key = this.BaseGetKey( index ); _de.Value = this.BaseGet( index ); return( _de ); } } // Gets or sets the value associated with the specified key. public Object this[ String key ] { get { return( this.BaseGet( key ) ); } set { this.BaseSet( key, value ); } } // Adds elements from an IDictionary into the new collection. public MyCollection( IDictionary d ) { foreach ( DictionaryEntry de in d ) { this.BaseAdd( (String) de.Key, de.Value ); } } } public class SamplesNameObjectCollectionBase { public static void Main() { // Creates and initializes a new MyCollection instance. IDictionary d = new ListDictionary(); d.Add( "red", "apple" ); d.Add( "yellow", "banana" ); d.Add( "green", "pear" ); MyCollection myCol = new MyCollection( d ); Console.WriteLine( "Initial state of the collection (Count = {0}):", myCol.Count ); PrintKeysAndValues( myCol ); // Gets specific keys and values. Console.WriteLine( "The key at index 0 is {0}.", myCol[0].Key ); Console.WriteLine( "The value at index 0 is {0}.", myCol[0].Value ); Console.WriteLine( "The value associated with the key \"green\" is {0}.", myCol["green"] ); } public static void PrintKeysAndValues( MyCollection myCol ) { for ( int i = 0; i < myCol.Count; i++ ) { Console.WriteLine( "[{0}] : {1}, {2}", i, myCol[i].Key, myCol[i].Value ); } } } /* This code produces the following output. Initial state of the collection (Count = 3): [0] : red, apple [1] : yellow, banana [2] : green, pear The key at index 0 is red. The value at index 0 is apple. The value associated with the key "green" is pear. */
Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
Available since 10
.NET Framework
Available since 1.1
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