KeyValuePair<TKey,TValue> Struct

Definition

Namespace:

System.Collections.Generic

Assembly:

System.Runtime.dll

Source:

KeyValuePair.cs

Defines a key/value pair that can be set or retrieved.

generic <typename TKey, typename TValue>
public value class KeyValuePair

public readonly struct KeyValuePair<TKey,TValue>

type KeyValuePair<'Key, 'Value> = struct

Public Structure KeyValuePair(Of TKey, TValue)

Type Parameters

TKey

The type of the key.

TValue

The type of the value.

Inheritance

Object

ValueType

KeyValuePair<TKey,TValue>

Examples

The following code example shows how to enumerate the keys and values in a dictionary, using the KeyValuePair<TKey,TValue> structure.

This code is part of a larger example provided for the Dictionary<TKey,TValue> class.

// 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

Remarks

The Dictionary<TKey,TValue>.Enumerator.Current property returns an instance of this type.

The foreach statement of the C# language (for each in C++, For Each in Visual Basic) returns an object of the type of the elements in the collection. Since each element of a collection based on IDictionary<TKey,TValue> is a key/value pair, the element type is not the type of the key or the type of the value. Instead, the element type is KeyValuePair<TKey,TValue>. For example:

for each(KeyValuePair<String^, String^> kvp in myDictionary)
{
    Console::WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);
}

foreach( KeyValuePair<string, string> kvp in myDictionary )
{
    Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value);
}

For Each kvp As KeyValuePair(Of String, String) In myDictionary
    Console.WriteLine("Key = {0}, Value = {1}", kvp.Key, kvp.Value)
Next kvp

The foreach statement is a wrapper around the enumerator, which allows only reading from, not writing to, the collection.

Constructors

KeyValuePair<TKey,TValue>(TKey, TValue)

Initializes a new instance of the KeyValuePair<TKey,TValue> structure with the specified key and value.

Properties

Key	Gets the key in the key/value pair.
Value	Gets the value in the key/value pair.

Methods

Deconstruct(TKey, TValue)	Deconstructs the current KeyValuePair<TKey,TValue>.
ToString()	Returns a string representation of the KeyValuePair<TKey,TValue>, using the string representations of the key and value.

See also

• IDictionary<TKey,TValue>
• Dictionary<TKey,TValue>.Enumerator
• DictionaryEntry