Tuple<'T1>.IStructuralComparable.CompareTo Method (Object, IComparer)


Compares the current Tuple<'T1> object to a specified object by using a specified comparer, and returns an integer that indicates whether the current object is before, after, or in the same position as the specified object in the sort order.

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

private abstract CompareTo : 
        other:Object *
        comparer:IComparer -> int
private override CompareTo : 
        other:Object *
        comparer:IComparer -> int


Type: System.Object

An object to compare with the current instance.

Type: System.Collections.IComparer

An object that provides custom rules for comparison.

Return Value

Type: System.Int32

A signed integer that indicates the relative position of this instance and other in the sort order, as shown in the following table.



A negative integer

This instance precedes other.


This instance and other have the same position in the sort order.

A positive integer

This instance follows other.

Exception Condition

other is not a Tuple<'T1> object.

Although this method can be called directly, it is most commonly called by collection sorting methods that include IComparer parameters to order the members of a collection. For example, it is called by the Array.Sort(Array, IComparer) method and the Add method of a SortedList object that is instantiated by using the SortedList.SortedList(IComparer) constructor.


The IStructuralComparable.CompareTo method is intended for use in sorting operations. It should not be used when the primary purpose of a comparison is to determine whether two objects are equal. To determine whether two objects are equal, call the IStructuralEquatable.Equals method.

The following example defines a generic class named DescendingComparer that implements the IComparer<'T> interface. DescendingComparer sorts objects in descending rather than ascending order by reversing the value returned by the default comparer for a particular type. An instance of the generic DescendingComparer class is then passed to the Array.Sort(Array, IComparer) method to sort an array of Tuple<'T1> objects in descending order. Note that the example does not directly call the IStructuralComparable.CompareTo method. This method is called implicitly by the Array.Sort(Array, IComparer) method for each element in the array.

No code example is currently available or this language may not be supported.

Universal Windows Platform
Available since 8
.NET Framework
Available since 4.0
Portable Class Library
Supported in: portable .NET platforms
Available since 4.0
Windows Phone Silverlight
Available since 8.0
Windows Phone
Available since 8.1
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