IStructuralComparable.CompareTo Method

Tuple(Of T1, T2, T3, T4, T5).IStructuralComparable.CompareTo Method (Object, IComparer)

.NET Framework (current version)

Compares the current Tuple(Of T1, T2, T3, T4, T5) 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


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

This member is an explicit interface member implementation. It can be used only when the Tuple(Of T1, T2, T3, T4, T5) 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. 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(Object, IEqualityComparer) method.

The following example creates an array of Tuple(Of T1, T2, T3, T4, T5) objects that contain career statistical data for running backs in American professional football. The 5-tuple's components consist of the player's name, the number of games in which he played, the number of carries or attempts, the total number of yards gained, and the number of touchdowns scored. The example displays the components of each tuple in the array in unsorted order, sorts the array, and then calls ToString to display each tuple in sorted order. To sort the array, the example defines a generic YardsGained class that implements the IComparer interface and sorts the Tuple(Of T1, T2, T3, T4, T5) objects in descending order by the value of their fourth component (yards gained) rather than by 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.

Imports System.Collections
Imports System.Collections.Generic

Public Class YardsGained(Of T1, T2, T3, T4, T5) : Implements IComparer
   Public Function Compare(x As Object, y As Object) As Integer _
                   Implements IComparer.Compare
      Dim tX As Tuple(Of T1, T2, T3, T4, T5) = TryCast(x, Tuple(Of T1, T2, T3, T4, T5))
      If tX Is Nothing Then
         Return 0
         Dim tY As Tuple(Of T1, T2, T3, T4, T5) = DirectCast(y, Tuple(Of T1, T2, T3, T4, T5))
         Return -1 * Comparer(Of T4).Default.Compare(tx.Item4, tY.Item4)             
      End If
   End Function
End Class

Module Example
   Public Sub Main()
      ' Organization of runningBacks 5-tuple:
      '    Component 1: Player name
      '    Component 2: Number of games played
      '    Component 3: Number of attempts (carries)
      '    Component 4: Number of yards gained 
      '    Component 5: Number of touchdowns   
      Dim runningBacks() =
          { Tuple.Create("Payton, Walter", 190, 3838, 16726, 110),  
            Tuple.Create("Sanders, Barry", 153, 3062, 15269, 99),            
            Tuple.Create("Brown, Jim", 118, 2359, 12312, 106),            
            Tuple.Create("Dickerson, Eric", 144, 2996, 13259, 90),            
            Tuple.Create("Faulk, Marshall", 176, 2836, 12279, 100) } 

      ' Display the array in unsorted order.
      Console.WriteLine("The values in unsorted order:")
      For Each runningBack In runningBacks

      ' Sort the array
      Array.Sort(runningBacks, New YardsGained(Of String, Integer, Integer, Integer, Integer)())

      ' Display the array in sorted order.
      Console.WriteLine("The values in sorted order:")
      For Each runningBack In runningBacks
   End Sub
End Module
' The example displays the following output:
'       The values in unsorted order:
'       (Payton, Walter, 190, 3838, 16726, 110)
'       (Sanders, Barry, 153, 3062, 15269, 99)
'       (Brown, Jim, 118, 2359, 12312, 106)
'       (Dickerson, Eric, 144, 2996, 13259, 90)
'       (Faulk, Marshall, 176, 2836, 12279, 100)
'       The values in sorted order:
'       (Payton, Walter, 190, 3838, 16726, 110)
'       (Sanders, Barry, 153, 3062, 15269, 99)
'       (Dickerson, Eric, 144, 2996, 13259, 90)
'       (Brown, Jim, 118, 2359, 12312, 106)
'       (Faulk, Marshall, 176, 2836, 12279, 100)

Universal Windows Platform
Available since 4.5
.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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