Defines a generalized comparison method that a value type or class implements to create a type-specific comparison method for ordering instances.
Assembly: mscorlib (in mscorlib.dll)
- 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 Covariance and Contravariance in Generics.
Thetype exposes the following members.
This interface is implemented by types whose values can be ordered, primarily for sorting. For example, one number can be larger than a second number, and one string can appear in alphabetical order before another. A value type or class implements the CompareTo(T) method to create a type-specific comparison method suitable for purposes such as sorting.
The interface defines the CompareTo(T) 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.
Less than zero
This object is less than the object specified by the CompareTo method.
This object is equal to the method parameter.
Greater than zero
This object is greater than the method parameter.
The interface provides a strongly typed comparison method for ordering members of a generic collection object. Because of this, it is usually not called directly from developer code. Instead, it is called automatically by methods such as List(T).Sort() and Add.Notes to Implementers
Replace the type parameter of the interface with the type that is implementing this interface.
If you implement , you should overload the op_GreaterThan, op_GreaterThanOrEqual, op_LessThan, and op_LessThanOrEqual operators to return values that are consistent with CompareTo. In addition, you should also implement IEquatable(T). See the IEquatable(T) article for complete information.
The following code example illustrates the implementation of for a simple Temperature object. The example creates a SortedList(TKey, TValue) collection of strings with Temperature object keys, and adds several pairs of temperatures and strings to the list out of sequence. In the call to the Add method, the SortedList(TKey, TValue) collection uses the implementation to sort the list entries, which are then displayed in order of increasing temperature.
.NET FrameworkSupported in: 4.5.2, 4.5.1, 4.5, 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
.NET for Windows Phone appsSupported in: Windows Phone 8.1, Windows Phone 8, Silverlight 8.1
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.