Windows Dev Center

IEqualityComparer<T> Interface

Defines methods to support the comparison of objects for equality.

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

public interface IEqualityComparer<in T>

Type Parameters

in T

The type of objects to compare.

This type parameter is contravariant. That is, you can use either the type you specified or any type that is less derived. For more information about covariance and contravariance, see [2678dc63-c7f9-4590-9ddc-0a4df684d42e].

The IEqualityComparer<T> type exposes the following members.

  NameDescription
Public methodEqualsDetermines whether the specified objects are equal.
Public methodGetHashCodeReturns a hash code for the specified object.
Top

This interface allows the implementation of customized equality comparison for collections. That is, you can create your own definition of equality for type T, and specify that this definition be used with a collection type that accepts the IEqualityComparer<T> generic interface. In the .NET Framework, constructors of the Dictionary<TKey, TValue> generic collection type accept this interface.

A default implementation of this interface is provided by the Default property of the EqualityComparer<T> generic class. The StringComparer class implements IEqualityComparer<T> of type String.

This interface supports only equality comparisons. Customization of comparisons for sorting and ordering is provided by the IComparer<T> generic interface.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

Show:
© 2015 Microsoft