Dictionary(TKey, TValue) Constructor (IDictionary(TKey, TValue), IEqualityComparer(TKey))

Dictionary<TKey, TValue> Constructor (IDictionary<TKey, TValue>, 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 contains elements copied from the specified IDictionary<TKey, TValue> and uses the specified IEqualityComparer<T>.

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

public Dictionary(
	IDictionary<TKey, TValue> dictionary,
	IEqualityComparer<TKey> comparer
)

Parameters

dictionary
Type: System.Collections.Generic.IDictionary<TKey, TValue>
The IDictionary<TKey, TValue> whose elements are copied to the new Dictionary<TKey, TValue>.
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.

ExceptionCondition
ArgumentNullException

dictionary is null.

ArgumentException

dictionary contains one or more duplicate keys.

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; likewise, every key in the source dictionary must also be unique according to the specified comparer.

NoteNote:

For example, duplicate keys can occur if comparer is one of the case-insensitive string comparers provided by the StringComparer class and dictionary does not use a case-insensitive comparer key.

The initial capacity of the new Dictionary<TKey, TValue> is large enough to contain all the elements in dictionary.

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.

This constructor is an O(n) operation, where n is the number of elements in dictionary.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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