Dictionary<TKey, TValue> Constructor (IEqualityComparer<TKey>)
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Initializes a new instance of the Dictionary<TKey, TValue> class that is empty, has the default initial capacity, and uses the specified IEqualityComparer<T>.
Namespace: System.Collections.Generic
Assembly: mscorlib (in mscorlib.dll)
Syntax
'Declaration
Public Sub New ( _
comparer As IEqualityComparer(Of TKey) _
)
public Dictionary(
IEqualityComparer<TKey> comparer
)
Parameters
- comparer
Type: System.Collections.Generic.IEqualityComparer<TKey>
The IEqualityComparer<T> implementation to use when comparing keys, or nulla null reference (Nothing in Visual Basic) to use the default EqualityComparer<T> for the type of the key.
Remarks
Use this constructor with the case-insensitive string comparers provided by the StringComparer class to create dictionaries with case-insensitive string keys.
Every key in a Dictionary<TKey, TValue> must be unique according to the specified comparer.
Dictionary<TKey, TValue> requires an equality implementation to determine whether keys are equal. If comparer is nulla null reference (Nothing in Visual Basic), this constructor uses the default generic equality comparer, EqualityComparer<T>.Default. If type TKey implements the System.IEquatable<T> generic interface, the default equality comparer uses that implementation.
.gif "Note") Note: |
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If you can estimate the size of the collection, using a constructor that specifies the initial capacity eliminates the need to perform a number of resizing operations while adding elements to the Dictionary<TKey, TValue>. |
This constructor is an O(1) operation.
Version Information
Silverlight
Supported in: 5, 4, 3
Silverlight for Windows Phone
Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0
XNA Framework
Supported in: Xbox 360, Windows Phone OS 7.0
Platforms
For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.