Dictionary<TKey, TValue> Constructor (IEqualityComparer<TKey>)
[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]
Initializes a new instance of the Dictionary<TKey, TValue> class that is empty, has the default initial capacity, and uses the specified IEqualityComparer<T>.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- comparer
- Type: System.Collections.Generic.IEqualityComparer<TKey>
The IEqualityComparer<T> implementation to use when comparing keys, or null to use the default EqualityComparer<T> for the type of the key.
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 null, 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.
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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.
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