Comparer.Compare Method (Object, Object)

 

Performs a case-sensitive comparison of two objects of the same type and returns a value indicating whether one is less than, equal to, or greater than the other.

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

Public Function Compare (
	a As Object,
	b As Object
) As Integer

Parameters

a
Type: System.Object

The first object to compare.

b
Type: System.Object

The second object to compare.

Return Value

Type: System.Int32

A signed integer that indicates the relative values of a and b, as shown in the following table.

Value

Meaning

Less than zero

a is less than b.

Zero

a equals b.

Greater than zero

a is greater than b.

Exception Condition
ArgumentException

Neither a nor b implements the IComparable interface.

-or-

a and b are of different types and neither one can handle comparisons with the other.

If a implements IComparable, then a. CompareTo (b) is returned; otherwise, if b implements IComparable, then the negated result of b. CompareTo (a) is returned.

Comparing null with any type is allowed and does not generate an exception when using IComparable. When sorting, null is considered to be less than any other object.

String comparisons might have different results depending on the culture. For more information on culture-specific comparisons, see the System.Globalization namespace and Globalizing and Localizing .NET Framework Applications.

The following code example shows how Compare returns different values depending on the culture associated with the Comparer.

Imports System
Imports System.Collections
Imports System.Globalization

Public Class SamplesComparer

   Public Shared Sub Main()

      ' Creates the strings to compare.
      Dim str1 As [String] = "llegar"
      Dim str2 As [String] = "lugar"
      Console.WriteLine("Comparing ""{0}"" and ""{1}"" ...", str1, str2)

      ' Uses the DefaultInvariant Comparer.
      Console.WriteLine("   Invariant Comparer: {0}", Comparer.DefaultInvariant.Compare(str1, str2))

      ' Uses the Comparer based on the culture "es-ES" (Spanish - Spain, international sort).
      Dim myCompIntl As New Comparer(New CultureInfo("es-ES", False))
      Console.WriteLine("   International Sort: {0}", myCompIntl.Compare(str1, str2))

      ' Uses the Comparer based on the culture identifier 0x040A (Spanish - Spain, traditional sort).
      Dim myCompTrad As New Comparer(New CultureInfo(&H40A, False))
      Console.WriteLine("   Traditional Sort  : {0}", myCompTrad.Compare(str1, str2))

   End Sub 'Main 

End Class 'SamplesComparer


'This code produces the following output.
'
'Comparing "llegar" and "lugar" ...
'   Invariant Comparer: -1
'   International Sort: -1
'   Traditional Sort  : 1

Universal Windows Platform
Available since 10
.NET Framework
Available since 1.1
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