KeyValuePair(TKey, TValue) Structure
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KeyValuePair<TKey, TValue> Structure


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

Namespace:   System.Collections.Generic
Assembly:  mscorlib (in mscorlib.dll)

public struct KeyValuePair<TKey, TValue>

Type Parameters


The type of the key.


The type of the value.

System_CAPS_pubmethodKeyValuePair<TKey, TValue>(TKey, TValue)

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


Gets the key in the key/value pair.


Gets the value in the key/value pair.


Indicates whether this instance and a specified object are equal.(Inherited from ValueType.)


Returns the hash code for this instance.(Inherited from ValueType.)


Gets the Type of the current instance.(Inherited from Object.)


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

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:

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

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

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

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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