KeyedCollection<TKey, TItem> Constructor (IEqualityComparer<TKey>)

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Initializes a new instance of the KeyedCollection<TKey, TItem> class that uses the specified equality comparer.

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

Syntax

'Declaration
Protected Sub New ( _
    comparer As IEqualityComparer(Of TKey) _
)

protected KeyedCollection(
    IEqualityComparer<TKey> comparer
)

comparer
Type: System.Collections.Generic.IEqualityComparer<TKey>
The implementation of the IEqualityComparer<T> generic interface to use when comparing keys, or nulla null reference (Nothing in Visual Basic) to use the default equality comparer for the type of the key, obtained from EqualityComparer<T>.Default.

By default, the KeyedCollection<TKey, TItem> includes a lookup dictionary that is created when the first item is added. When an item is added to the KeyedCollection<TKey, TItem>, the item's key is extracted once and saved in the lookup dictionary for faster searches. This behavior can be overridden by using the KeyedCollection<TKey, TItem>(IEqualityComparer<TKey>, Int32) constructor and specifying a dictionary creation threshold.

Note:
Because the KeyedCollection<TKey, TItem> class is abstract (MustInherit in Visual Basic), you must derive from it in order to use it. In the constructor for your derived type, call the appropriate KeyedCollection<TKey, TItem> constructor. It is not necessary to expose functionality like the equality comparer or the dictionary creation threshold in your constructors.

This constructor is an O(1) operation.

Supported in: 5, 4, 3

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

Supported in: Xbox 360, Windows Phone OS 7.0

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.