KeyValuePair<TKey, TValue> Structure


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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 8
.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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