Dictionary<TKey,TValue>.IDictionary.Keys Dictionary<TKey,TValue>.IDictionary.Keys Dictionary<TKey,TValue>.IDictionary.Keys Property

定義

ICollection のキーを保持している IDictionary を取得します。Gets an ICollection containing the keys of the IDictionary.

property System::Collections::ICollection ^ System::Collections::IDictionary::Keys { System::Collections::ICollection ^ get(); };
System.Collections.ICollection System.Collections.IDictionary.Keys { get; }
 ReadOnly Property Keys As ICollection Implements IDictionary.Keys

プロパティ値

ICollection のキーを保持している IDictionaryAn ICollection containing the keys of the IDictionary.

実装

次のコード例は、と共IDictionary.Keys Dictionary<TKey,TValue>System.Collections.IDictionaryインターフェイスのプロパティを使用して、ディクショナリ内のキーを一覧表示する方法を示しています。The following code example shows how to use the IDictionary.Keys property of the System.Collections.IDictionary interface with a Dictionary<TKey,TValue>, to list the keys in the dictionary. この例では、ディクショナリ内のキーと値のペアを列挙する方法も示しています。System.Collections.IDictionaryインターフェイスの列挙子は、 KeyValuePair<TKey,TValue>オブジェクトでDictionaryEntryはなくオブジェクトを返すことに注意してください。The example also shows how to enumerate the key/value pairs in the dictionary; note that the enumerator for the System.Collections.IDictionary interface returns DictionaryEntry objects rather than KeyValuePair<TKey,TValue> objects.

このコード例は、 IDictionary.Addメソッドに指定された出力を含む、より大きな例の一部です。The code example is part of a larger example, including output, provided for the IDictionary.Add method.

using System;
using System.Collections;
using System.Collections.Generic;

public class Example
{
    public static void Main()
    {
        // Create a new dictionary of strings, with string keys,
        // and access it using the IDictionary interface.
        //
        IDictionary openWith = new Dictionary<string, string>();

        // Add some elements to the dictionary. There are no 
        // duplicate keys, but some of the values are duplicates.
        // IDictionary.Add throws an exception if incorrect types
        // are supplied for key or value.
        openWith.Add("txt", "notepad.exe");
        openWith.Add("bmp", "paint.exe");
        openWith.Add("dib", "paint.exe");
        openWith.Add("rtf", "wordpad.exe");
Imports System
Imports System.Collections
Imports System.Collections.Generic

Public Class Example
    
    Public Shared Sub Main() 

        ' Create a new dictionary of strings, with string keys,
        ' and access it using the IDictionary interface.
        '
        Dim openWith As IDictionary = _
            New Dictionary(Of String, String)
        
        ' Add some elements to the dictionary. There are no 
        ' duplicate keys, but some of the values are duplicates.
        ' IDictionary.Add throws an exception if incorrect types
        ' are supplied for key or value.
        openWith.Add("txt", "notepad.exe")
        openWith.Add("bmp", "paint.exe")
        openWith.Add("dib", "paint.exe")
        openWith.Add("rtf", "wordpad.exe")
// To get the keys alone, use the Keys property.
icoll = openWith.Keys;

// The elements of the collection are strongly typed
// with the type that was specified for dictionary keys,
// even though the ICollection interface is not strongly
// typed.
Console.WriteLine();
foreach( string s in icoll )
{
    Console.WriteLine("Key = {0}", s);
}
' To get the keys alone, use the Keys property.
icoll = openWith.Keys

' The elements of the collection are strongly typed
' with the type that was specified for dictionary keys,
' even though the ICollection interface is not strongly
' typed.
Console.WriteLine()
For Each s As String In  icoll
    Console.WriteLine("Key = {0}", s)
Next s
// When you use foreach to enumerate dictionary elements
// with the IDictionary interface, the elements are retrieved
// as DictionaryEntry objects instead of KeyValuePair objects.
Console.WriteLine();
foreach( DictionaryEntry de in openWith )
{
    Console.WriteLine("Key = {0}, Value = {1}", 
        de.Key, de.Value);
}
' When you use foreach to enumerate dictionary elements
' with the IDictionary interface, the elements are retrieved
' as DictionaryEntry objects instead of KeyValuePair objects.
Console.WriteLine()
For Each de As DictionaryEntry In openWith
    Console.WriteLine("Key = {0}, Value = {1}", _
        de.Key, de.Value)
Next 
    }
}

    End Sub

End Class

注釈

返されるICollectionのキーの順序は指定されていませんが、 ValuesプロパティによってICollection返される内の対応する値と同じ順序であることが保証されます。The order of the keys in the returned ICollection is unspecified, but it is guaranteed to be the same order as the corresponding values in the ICollection returned by the Values property.

このプロパティの値の取得は O (1) 操作です。Getting the value of this property is an O(1) operation.

適用対象

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