IDictionary<TKey,TValue> IDictionary<TKey,TValue> IDictionary<TKey,TValue> IDictionary<TKey,TValue> Interface

Definition

Представляет универсальную коллекцию пар «ключ-значение». Represents a generic collection of key/value pairs.

generic <typename TKey, typename TValue>
public interface class IDictionary : System::Collections::Generic::ICollection<System::Collections::Generic::KeyValuePair<TKey, TValue>>, System::Collections::Generic::IEnumerable<System::Collections::Generic::KeyValuePair<TKey, TValue>>
public interface IDictionary<TKey,TValue> : System.Collections.Generic.ICollection<System.Collections.Generic.KeyValuePair<TKey,TValue>>, System.Collections.Generic.IEnumerable<System.Collections.Generic.KeyValuePair<TKey,TValue>>
type IDictionary<'Key, 'Value> = interface
    interface ICollection<KeyValuePair<'Key, 'Value>>
    interface seq<KeyValuePair<'Key, 'Value>>
    interface IEnumerable
Public Interface IDictionary(Of TKey, TValue)
Implements ICollection(Of KeyValuePair(Of TKey, TValue)), IEnumerable(Of KeyValuePair(Of TKey, TValue))

Type Parameters

TKey

Тип ключей в словаре. The type of keys in the dictionary.

TValue

Тип значений в словаре. The type of values in the dictionary.

Derived
Implements

Examples

В следующем примере кода создается пустой Dictionary<TKey,TValue> строк, со строкой ключи и доступ осуществляется через IDictionary<TKey,TValue> интерфейс.The following code example creates an empty Dictionary<TKey,TValue> of strings, with string keys, and accesses it through the IDictionary<TKey,TValue> interface.

В примере кода используется Add метод для добавления некоторых элементов.The code example uses the Add method to add some elements. В примере показывается, Add вызывает метод ArgumentException при попытке добавить повторяющийся ключ.The example demonstrates that the Add method throws ArgumentException when attempting to add a duplicate key.

В примере используется Item[TKey] (индексатор в C#) для получения значений, демонстрируя, что KeyNotFoundException возникает, если запрошенный ключ не указан, и отображение, что значение, связанное с ключом может быть заменен.The example uses the Item[TKey] property (the indexer in C#) to retrieve values, demonstrating that a KeyNotFoundException is thrown when a requested key is not present, and showing that the value associated with a key can be replaced.

В примере показано использование TryGetValue метод как более эффективный способ для получения значений программы часто пытающейся значениями ключа, которые не находятся в словаре и как использовать ContainsKey метод для проверки наличия ключа перед вызовом Addметод.The example shows how to use the TryGetValue method as a more efficient way to retrieve values if a program often must try key values that are not in the dictionary, and how to use the ContainsKey method to test whether a key exists prior to calling the Add method.

Наконец, в примере показано, как перечисление ключей и значений в словаре и как выполнить перечисление только с помощью значений Values свойство.Finally, the example shows how to enumerate the keys and values in the dictionary, and how to enumerate the values alone using the Values property.

using namespace System;
using namespace System::Collections::Generic;

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

        // Add some elements to the dictionary. There are no
        // duplicate keys, but some of the values are duplicates.
        openWith->Add("txt", "notepad.exe");
        openWith->Add("bmp", "paint.exe");
        openWith->Add("dib", "paint.exe");
        openWith->Add("rtf", "wordpad.exe");

        // The Add method throws an exception if the new key is
        // already in the dictionary.
        try
        {
            openWith->Add("txt", "winword.exe");
        }
        catch (ArgumentException^)
        {
            Console::WriteLine("An element with Key = \"txt\" already exists.");
        }

        // The Item property is another name for the indexer, so you
        // can omit its name when accessing elements.
        Console::WriteLine("For key = \"rtf\", value = {0}.",
            openWith["rtf"]);

        // The indexer can be used to change the value associated
        // with a key.
        openWith["rtf"] = "winword.exe";
        Console::WriteLine("For key = \"rtf\", value = {0}.",
            openWith["rtf"]);

        // If a key does not exist, setting the indexer for that key
        // adds a new key/value pair.
        openWith["doc"] = "winword.exe";

        // The indexer throws an exception if the requested key is
        // not in the dictionary.
        try
        {
            Console::WriteLine("For key = \"tif\", value = {0}.",
                openWith["tif"]);
        }
        catch (KeyNotFoundException^)
        {
            Console::WriteLine("Key = \"tif\" is not found.");
        }

        // When a program often has to try keys that turn out not to
        // be in the dictionary, TryGetValue can be a more efficient
        // way to retrieve values.
        String^ value = "";
        if (openWith->TryGetValue("tif", value))
        {
            Console::WriteLine("For key = \"tif\", value = {0}.", value);
        }
        else
        {
            Console::WriteLine("Key = \"tif\" is not found.");
        }

        // ContainsKey can be used to test keys before inserting
        // them.
        if (!openWith->ContainsKey("ht"))
        {
            openWith->Add("ht", "hypertrm.exe");
            Console::WriteLine("Value added for key = \"ht\": {0}",
                openWith["ht"]);
        }

        // 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);
        }

        // To get the values alone, use the Values property.
        ICollection<String^>^ icoll = openWith->Values;

        // The elements of the ValueCollection are strongly typed
        // with the type that was specified for dictionary values.
        Console::WriteLine();
        for each( String^ s in icoll )
        {
            Console::WriteLine("Value = {0}", s);
        }

        // To get the keys alone, use the Keys property.
        icoll = openWith->Keys;

        // The elements of the ValueCollection are strongly typed
        // with the type that was specified for dictionary values.
        Console::WriteLine();
        for each( String^ s in icoll )
        {
            Console::WriteLine("Key = {0}", s);
        }

        // Use the Remove method to remove a key/value pair.
        Console::WriteLine("\nRemove(\"doc\")");
        openWith->Remove("doc");

        if (!openWith->ContainsKey("doc"))
        {
            Console::WriteLine("Key \"doc\" is not found.");
        }
    }
};

int main()
{
    Example::Main();
}

/* This code example produces the following output:

An element with Key = "txt" already exists.
For key = "rtf", value = wordpad.exe.
For key = "rtf", value = winword.exe.
Key = "tif" is not found.
Key = "tif" is not found.
Value added for key = "ht": hypertrm.exe

Key = txt, Value = notepad.exe
Key = bmp, Value = paint.exe
Key = dib, Value = paint.exe
Key = rtf, Value = winword.exe
Key = doc, Value = winword.exe
Key = ht, Value = hypertrm.exe

Value = notepad.exe
Value = paint.exe
Value = paint.exe
Value = winword.exe
Value = winword.exe
Value = hypertrm.exe

Key = txt
Key = bmp
Key = dib
Key = rtf
Key = doc
Key = ht

Remove("doc")
Key "doc" is not found.
 */
using System;
using System.Collections.Generic;

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

        // Add some elements to the dictionary. There are no 
        // duplicate keys, but some of the values are duplicates.
        openWith.Add("txt", "notepad.exe");
        openWith.Add("bmp", "paint.exe");
        openWith.Add("dib", "paint.exe");
        openWith.Add("rtf", "wordpad.exe");

        // The Add method throws an exception if the new key is 
        // already in the dictionary.
        try
        {
            openWith.Add("txt", "winword.exe");
        }
        catch (ArgumentException)
        {
            Console.WriteLine("An element with Key = \"txt\" already exists.");
        }

        // The Item property is another name for the indexer, so you 
        // can omit its name when accessing elements. 
        Console.WriteLine("For key = \"rtf\", value = {0}.", 
            openWith["rtf"]);

        // The indexer can be used to change the value associated
        // with a key.
        openWith["rtf"] = "winword.exe";
        Console.WriteLine("For key = \"rtf\", value = {0}.", 
            openWith["rtf"]);

        // If a key does not exist, setting the indexer for that key
        // adds a new key/value pair.
        openWith["doc"] = "winword.exe";

        // The indexer throws an exception if the requested key is
        // not in the dictionary.
        try
        {
            Console.WriteLine("For key = \"tif\", value = {0}.", 
                openWith["tif"]);
        }
        catch (KeyNotFoundException)
        {
            Console.WriteLine("Key = \"tif\" is not found.");
        }

        // When a program often has to try keys that turn out not to
        // be in the dictionary, TryGetValue can be a more efficient 
        // way to retrieve values.
        string value = "";
        if (openWith.TryGetValue("tif", out value))
        {
            Console.WriteLine("For key = \"tif\", value = {0}.", value);
        }
        else
        {
            Console.WriteLine("Key = \"tif\" is not found.");
        }

        // ContainsKey can be used to test keys before inserting 
        // them.
        if (!openWith.ContainsKey("ht"))
        {
            openWith.Add("ht", "hypertrm.exe");
            Console.WriteLine("Value added for key = \"ht\": {0}", 
                openWith["ht"]);
        }

        // 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);
        }

        // To get the values alone, use the Values property.
        ICollection<string> icoll = openWith.Values;

        // The elements of the ValueCollection are strongly typed
        // with the type that was specified for dictionary values.
        Console.WriteLine();
        foreach( string s in icoll )
        {
            Console.WriteLine("Value = {0}", s);
        }

        // To get the keys alone, use the Keys property.
        icoll = openWith.Keys;

        // The elements of the ValueCollection are strongly typed
        // with the type that was specified for dictionary values.
        Console.WriteLine();
        foreach( string s in icoll )
        {
            Console.WriteLine("Key = {0}", s);
        }

        // Use the Remove method to remove a key/value pair.
        Console.WriteLine("\nRemove(\"doc\")");
        openWith.Remove("doc");

        if (!openWith.ContainsKey("doc"))
        {
            Console.WriteLine("Key \"doc\" is not found.");
        }
    }
}

/* This code example produces the following output:

An element with Key = "txt" already exists.
For key = "rtf", value = wordpad.exe.
For key = "rtf", value = winword.exe.
Key = "tif" is not found.
Key = "tif" is not found.
Value added for key = "ht": hypertrm.exe

Key = txt, Value = notepad.exe
Key = bmp, Value = paint.exe
Key = dib, Value = paint.exe
Key = rtf, Value = winword.exe
Key = doc, Value = winword.exe
Key = ht, Value = hypertrm.exe

Value = notepad.exe
Value = paint.exe
Value = paint.exe
Value = winword.exe
Value = winword.exe
Value = hypertrm.exe

Key = txt
Key = bmp
Key = dib
Key = rtf
Key = doc
Key = ht

Remove("doc")
Key "doc" is not found.
 */
Imports System
Imports System.Collections.Generic

Public Class Example
    
    Public Shared Sub Main() 

        ' Create a new dictionary of strings, with string keys, 
        ' and access it through the IDictionary generic interface.
        Dim openWith As IDictionary(Of String, String) = _
            New Dictionary(Of String, String)
        
        ' Add some elements to the dictionary. There are no 
        ' duplicate keys, but some of the values are duplicates.
        openWith.Add("txt", "notepad.exe")
        openWith.Add("bmp", "paint.exe")
        openWith.Add("dib", "paint.exe")
        openWith.Add("rtf", "wordpad.exe")
        
        ' The Add method throws an exception if the new key is 
        ' already in the dictionary.
        Try
            openWith.Add("txt", "winword.exe")
        Catch 
            Console.WriteLine("An element with Key = ""txt"" already exists.")
        End Try

        ' The Item property is the default property, so you 
        ' can omit its name when accessing elements. 
        Console.WriteLine("For key = ""rtf"", value = {0}.", _
            openWith("rtf"))
        
        ' The default Item property can be used to change the value
        ' associated with a key.
        openWith("rtf") = "winword.exe"
        Console.WriteLine("For key = ""rtf"", value = {0}.", _
            openWith("rtf"))
        
        ' If a key does not exist, setting the default item property
        ' for that key adds a new key/value pair.
        openWith("doc") = "winword.exe"

        ' The default Item property throws an exception if the requested
        ' key is not in the dictionary.
        Try
            Console.WriteLine("For key = ""tif"", value = {0}.", _
                openWith("tif"))
        Catch 
            Console.WriteLine("Key = ""tif"" is not found.")
        End Try

        ' When a program often has to try keys that turn out not to
        ' be in the dictionary, TryGetValue can be a more efficient 
        ' way to retrieve values.
        Dim value As String = ""
        If openWith.TryGetValue("tif", value) Then
            Console.WriteLine("For key = ""tif"", value = {0}.", value)
        Else
            Console.WriteLine("Key = ""tif"" is not found.")
        End If

        ' ContainsKey can be used to test keys before inserting 
        ' them.
        If Not openWith.ContainsKey("ht") Then
            openWith.Add("ht", "hypertrm.exe")
            Console.WriteLine("Value added for key = ""ht"": {0}", _
                openWith("ht"))
        End If

        ' 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

        ' To get the values alone, use the Values property.
        Dim icoll As ICollection(Of String) = openWith.Values
        
        ' The elements of the ValueCollection are strongly typed
        ' with the type that was specified for dictionary values.
        Console.WriteLine()
        For Each s As String In  icoll
            Console.WriteLine("Value = {0}", s)
        Next s

        ' To get the keys alone, use the Keys property.
        icoll = openWith.Keys
        
        ' The elements of the ValueCollection are strongly typed
        ' with the type that was specified for dictionary values.
        Console.WriteLine()
        For Each s As String In  icoll
            Console.WriteLine("Key = {0}", s)
        Next s

        ' Use the Remove method to remove a key/value pair.
        Console.WriteLine(vbLf + "Remove(""doc"")")
        openWith.Remove("doc")
        
        If Not openWith.ContainsKey("doc") Then
            Console.WriteLine("Key ""doc"" is not found.")
        End If

    End Sub

End Class

' This code example produces the following output:
'
'An element with Key = "txt" already exists.
'For key = "rtf", value = wordpad.exe.
'For key = "rtf", value = winword.exe.
'Key = "tif" is not found.
'Key = "tif" is not found.
'Value added for key = "ht": hypertrm.exe
'
'Key = txt, Value = notepad.exe
'Key = bmp, Value = paint.exe
'Key = dib, Value = paint.exe
'Key = rtf, Value = winword.exe
'Key = doc, Value = winword.exe
'Key = ht, Value = hypertrm.exe
'
'Value = notepad.exe
'Value = paint.exe
'Value = paint.exe
'Value = winword.exe
'Value = winword.exe
'Value = hypertrm.exe
'
'Key = txt
'Key = bmp
'Key = dib
'Key = rtf
'Key = doc
'Key = ht
'
'Remove("doc")
'Key "doc" is not found.
' 

Remarks

IDictionary<TKey,TValue> Это базовый интерфейс для универсальных коллекций пар "ключ значение".The IDictionary<TKey,TValue> interface is the base interface for generic collections of key/value pairs.

Каждый элемент представляет пару ключ значение, хранящиеся в KeyValuePair<TKey,TValue> объекта.Each element is a key/value pair stored in a KeyValuePair<TKey,TValue> object.

Каждая пара должна иметь уникальный ключ.Each pair must have a unique key. Реализации могут различаться по, допускают ли они key быть null.Implementations can vary in whether they allow key to be null. Значение может быть null и не быть уникальным.The value can be null and does not have to be unique. IDictionary<TKey,TValue> Интерфейс позволяет автономной ключи и значения, которые необходимо перечислить, но это не означает любой определенного порядка сортировки.The IDictionary<TKey,TValue> interface allows the contained keys and values to be enumerated, but it does not imply any particular sort order.

foreach Инструкции языка C# (For Each в Visual Basic, for each в C++) возвращает объект типа элементов в коллекции.The foreach statement of the C# language (For Each in Visual Basic, for each in C++) returns an object of the type of the elements in the collection. Так как каждый элемент из IDictionary<TKey,TValue> — это пара ключ/значение, тип элемента не является типом ключа или тип значения.Since each element of the IDictionary<TKey,TValue> is a key/value pair, the element type is not the type of the key or the type of the value. Вместо этого тип элемента — это KeyValuePair<TKey,TValue>.Instead, the element type is KeyValuePair<TKey,TValue>. Пример:For example:

for each(KeyValuePair<int, String^> kvp in myDictionary)
{
    Console::WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);
}
foreach (KeyValuePair<int, string> kvp in myDictionary)
{
    Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);
}
For Each kvp As KeyValuePair(Of Integer, String) In myDictionary
    Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value)
Next kvp

foreach Инструкция — это оболочка вокруг перечислитель, который допускает только чтение из, но не запись в коллекции.The foreach statement is a wrapper around the enumerator, which only allows reading from, not writing to, the collection.

Примечание

Так как может быть унаследован ключи и их поведение изменено, абсолютная уникальность не гарантируется при сравнении с Equals метод.Because keys can be inherited and their behavior changed, their absolute uniqueness cannot be guaranteed by comparisons using the Equals method.

Notes to Implementers

Реализующий класс должен иметь средства для сравнения ключей. The implementing class must have a means to compare keys.

Properties

Item[TKey] Item[TKey] Item[TKey] Item[TKey]

Возвращает или задает элемент с указанным ключом. Gets or sets the element with the specified key.

Keys Keys Keys Keys

Возвращает интерфейс ICollection<T>, содержащий ключи IDictionary<TKey,TValue>. Gets an ICollection<T> containing the keys of the IDictionary<TKey,TValue>.

Values Values Values Values

Возвращает интерфейс ICollection<T>, содержащий значения из IDictionary<TKey,TValue>. Gets an ICollection<T> containing the values in the IDictionary<TKey,TValue>.

Methods

Add(TKey, TValue) Add(TKey, TValue) Add(TKey, TValue) Add(TKey, TValue)

Добавляет элемент с указанными ключом и значением в объект IDictionary<TKey,TValue>. Adds an element with the provided key and value to the IDictionary<TKey,TValue>.

ContainsKey(TKey) ContainsKey(TKey) ContainsKey(TKey) ContainsKey(TKey)

Определяет, содержится ли элемент с указанным ключом в IDictionary<TKey,TValue>. Determines whether the IDictionary<TKey,TValue> contains an element with the specified key.

Remove(TKey) Remove(TKey) Remove(TKey) Remove(TKey)

Удаляет элемент с указанным ключом из IDictionary<TKey,TValue>. Removes the element with the specified key from the IDictionary<TKey,TValue>.

TryGetValue(TKey, TValue) TryGetValue(TKey, TValue) TryGetValue(TKey, TValue) TryGetValue(TKey, TValue)

Возвращает значение, связанное с заданным ключом. Gets the value associated with the specified key.

Applies to

See Also