Tuple<(Of <(T1, T2>)>).IStructuralComparable.CompareTo Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

Compares the current Tuple<(Of <(T1, T2>)>) 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 Function CompareTo ( _
    other As Object, _
    comparer As IComparer _
) As Integer Implements IStructuralComparable.CompareTo
int IStructuralComparable.CompareTo(
    Object other,
    IComparer comparer


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.


IStructuralComparable..::.CompareTo(Object, IComparer)


Exception Condition

other is not a Tuple<(Of <(T1, T2>)>) object.


This member is an explicit interface member implementation. It can be used only when the Tuple<(Of <(T1, T2>)>) instance is cast to an IStructuralComparable interface.

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, such as the Array..::.Sort(Array, IComparer) method.


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 creates an array of Tuple<(Of <(T1, T2>)>) objects that consist of a student's name and test score. It displays the component of each tuple in the array in unsorted order, sorts the array, and then calls ToString to display the value of each tuple in sorted order. To sort the array, the example defines a generic ScoreComparer class that implements the IComparer interface and sorts the Tuple<(Of <(T1, T2>)>) objects in ascending order by the value of their second component rather than their first component. 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.

Version Information

Windows Phone OS

Supported in: 8.1, 8.0

See Also


Tuple<(Of <(T1, T2>)>) Class

System Namespace