Article
11/18/2011

Comparer<T> Class

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Provides a base class for implementations of the IComparer<T> generic interface.

Inheritance Hierarchy

System.Object
System.Collections.Generic.Comparer<T>

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

Syntax

'Declaration
Public MustInherit Class Comparer(Of T) _
    Implements IComparer, IComparer(Of T)

public abstract class Comparer<T> : IComparer, 
    IComparer<T>

Type Parameters

T
The type of objects to compare.

The Comparer<T> type exposes the following members.

Constructors

	Name	Description
	Comparer<T>	Initializes a new instance of the Comparer<T> class.

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Properties

	Name	Description
	Default	Returns a default sort order comparer for the type specified by the generic argument.

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Methods

	Name	Description
	Compare	When overridden in a derived class, performs a comparison of two objects of the same type and returns a value indicating whether one object is less than, equal to, or greater than the other.
	Equals(Object)	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an object to try to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	ToString	Returns a string that represents the current object. (Inherited from Object.)

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Explicit Interface Implementations

	Name	Description
	IComparer.Compare	Compares two objects and returns a value indicating whether one is less than, equal to, or greater than the other.

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Remarks

Derive from this class to provide a custom implementation of the IComparer<T> interface for use with collection classes.

The object returned by the Default property uses the System.IComparable<T> generic interface (IComparable<T> in C#, IComparable(Of T) in Visual Basic) to compare two objects. If type T does not implement the System.IComparable<T> generic interface, the Default property returns a Comparer<T> that uses the System.IComparable interface.

Notes to Implementers

Compare and EqualityComparer<T>.Equals may behave differently in terms of culture-sensitivity and case-sensitivity.

For string comparisons, the StringComparer class is recommended over Comparer<String>. Properties of the StringComparer class return predefined instances that perform string comparisons with different combinations of culture-sensitivity and case-sensitivity. The case-sensitivity and culture-sensitivity are consistent among the members of the same StringComparer instance.

For more information on culture-specific comparisons, see the System.Globalization namespace.

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

Thread Safety

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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