IEquatable<T> Interface

May 11, 2014

Defines a generalized method that a value type or class implements to create a type-specific method for determining equality of instances.

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

public interface IEquatable<T>

Type Parameters

T

The type of objects to compare.

The IEquatable<T> type exposes the following members.

  NameDescription
Public methodEqualsIndicates whether the current object is equal to another object of the same type.
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This interface is implemented by types whose values can be equated (for example, the numeric and string classes). A value type or class implements the Equals method to create a type-specific method suitable for determining equality of instances.

NoteNote:

The IComparable<T> interface defines the CompareTo method, which determines the sort order of instances of the implementing type. The IEquatable<T> interface defines the Equals method, which determines the equality of instances of the implementing type.

The IEquatable<T> interface is used by generic collection objects such as Dictionary<TKey, TValue>, List<T>, and LinkedList<T> when testing for equality in such methods as Contains, IndexOf, LastIndexOf, and Remove. It should be implemented for any object that might be stored in a generic collection.

Notes to Implementers

Replace the type parameter of the IEquatable<T> interface with the type that is implementing this interface.

If you implement IEquatable<T>, you should also override the base class implementations of Object.Equals(Object) and GetHashCode so that their behavior is consistent with that of the IEquatable<T>.Equals method. If you do override Object.Equals(Object), your overridden implementation is also called in calls to the static Equals(System.Object, System.Object) method on your class. This ensures that all invocations of the Equals method return consistent results.

See the example for the IEquatable<T>.Equals method.

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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