Defines a generalized method that a value type or class implements to create a type-specific method for determining equality of instances.
Assemblies: System.Runtime (in System.Runtime.dll)
mscorlib (in mscorlib.dll)
Thetype exposes the following members.
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.
The IComparable<T> interface defines the CompareTo method, which determines the sort order of instances of the implementing type. The interface defines the Equals method, which determines the equality of instances of the implementing type.
The 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 interface with the type that is implementing this interface.
If you implement , 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. In addition, you should overload the op_Equality and op_Inequality operators. This ensures that all tests for equality return consistent results.
For a value type, you should always implement and override Object.Equals(Object) for better performance. Object.Equals boxes value types and relies on reflection to compare two values for equality. Both your implementation of Equals and your override of Object.Equals should return consistent results.
.NET FrameworkSupported in: 4.5.3, 4, 3.5, 3.0, 2.0
.NET Framework Client ProfileSupported in: 4, 3.5 SP1
Portable Class LibrarySupported in: Portable Class Library
.NET for Windows Store appsSupported in: Windows 8
Supported in: Windows Phone 8.1
Supported in: Windows Phone Silverlight 8.1
Supported in: Windows Phone Silverlight 8
Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.