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

定義

取得集合,包含 Dictionary<TKey,TValue> 中的索引鍵。Gets a collection containing the keys in the Dictionary<TKey,TValue>.

public:
 property System::Collections::Generic::Dictionary<TKey, TValue>::KeyCollection ^ Keys { System::Collections::Generic::Dictionary<TKey, TValue>::KeyCollection ^ get(); };
public System.Collections.Generic.Dictionary<TKey,TValue>.KeyCollection Keys { get; }
member this.Keys : System.Collections.Generic.Dictionary<'Key, 'Value>.KeyCollection
Public ReadOnly Property Keys As Dictionary(Of TKey, TValue).KeyCollection

屬性值

範例

下列程式碼範例顯示如何使用Keys屬性列舉字典中的索引鍵,以及如何列舉字典中的索引鍵和值。The following code example shows how to enumerate the keys in the dictionary using the Keys property, and how to enumerate the keys and values in the dictionary.

此程式碼是可編譯和執行之較大範例的一部分(openWith這是此範例中使用的字典名稱)。This code is part of a larger example that can be compiled and executed (openWith is the name of the Dictionary used in this example). 請參閱 Dictionary<TKey,TValue>See Dictionary<TKey,TValue>.

// To get the keys alone, use the Keys property.
Dictionary<String^, String^>::KeyCollection^ keyColl =
    openWith->Keys;

// The elements of the KeyCollection are strongly typed
// with the type that was specified for dictionary keys.
Console::WriteLine();
for each( String^ s in keyColl )
{
    Console::WriteLine("Key = {0}", s);
}
// To get the keys alone, use the Keys property.
Dictionary<string, string>.KeyCollection keyColl =
    openWith.Keys;

// The elements of the KeyCollection are strongly typed
// with the type that was specified for dictionary keys.
Console.WriteLine();
foreach( string s in keyColl )
{
    Console.WriteLine("Key = {0}", s);
}
' To get the keys alone, use the Keys property.
Dim keyColl As _
    Dictionary(Of String, String).KeyCollection = _
    openWith.Keys

' The elements of the KeyCollection are strongly typed
' with the type that was specified for dictionary keys.
Console.WriteLine()
For Each s As String In  keyColl
    Console.WriteLine("Key = {0}", s)
Next s
// When you use foreach to enumerate dictionary elements,
// the elements are retrieved as KeyValuePair objects.
Console::WriteLine();
for each( KeyValuePair<String^, String^> kvp in openWith )
{
    Console::WriteLine("Key = {0}, Value = {1}",
        kvp.Key, kvp.Value);
}
// When you use foreach to enumerate dictionary elements,
// the elements are retrieved as KeyValuePair objects.
Console.WriteLine();
foreach( KeyValuePair<string, string> kvp in openWith )
{
    Console.WriteLine("Key = {0}, Value = {1}", 
        kvp.Key, kvp.Value);
}
' When you use foreach to enumerate dictionary elements,
' the elements are retrieved as KeyValuePair objects.
Console.WriteLine()
For Each kvp As KeyValuePair(Of String, String) In openWith
    Console.WriteLine("Key = {0}, Value = {1}", _
        kvp.Key, kvp.Value)
Next kvp

備註

Dictionary<TKey,TValue>.KeyCollection的索引鍵順序並未指定,但其順序與Values屬性Dictionary<TKey,TValue>.ValueCollection傳回之中關聯的值相同。The order of the keys in the Dictionary<TKey,TValue>.KeyCollection is unspecified, but it is the same order as the associated values in the Dictionary<TKey,TValue>.ValueCollection returned by the Values property.

傳回Dictionary<TKey,TValue>.KeyCollection的不是靜態複本Dictionary<TKey,TValue>.KeyCollection ,而是指回原始Dictionary<TKey,TValue>中的索引鍵。The returned Dictionary<TKey,TValue>.KeyCollection is not a static copy; instead, the Dictionary<TKey,TValue>.KeyCollection refers back to the keys in the original Dictionary<TKey,TValue>. 因此,的Dictionary<TKey,TValue>變更會繼續反映Dictionary<TKey,TValue>.KeyCollection在中。Therefore, changes to the Dictionary<TKey,TValue> continue to be reflected in the Dictionary<TKey,TValue>.KeyCollection.

取得這個屬性的值是 O (1)運算。Getting the value of this property is an O(1) operation.

適用於

另請參閱