Compare Method
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IComparer::Compare Method (Object^, Object^)


Compares two objects 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)

int Compare(
	Object^ x,
	Object^ y


Type: System::Object^

The first object to compare.

Type: System::Object^

The second object to compare.

Return Value

Type: System::Int32

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



Less than zero

x is less than y.


x equals y.

Greater than zero

x is greater than y.

Exception Condition

Neither x nor y implements the IComparable interface.


x and y are of different types and neither one can handle comparisons with the other.

The preferred implementation is to use the CompareTo method of one of the parameters.

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.

The following code example demonstrates the use of the IComparer interface to sort an ArrayList object. In this example, the IComparer interface is implemented using the CaseInsensitiveComparerclass to reverse the order of the contents of the ArrayList.

using namespace System;
using namespace System::Collections;
void PrintIndexAndValues( IEnumerable^ myList );
ref class myReverserClass: public IComparer

   // Calls CaseInsensitiveComparer.Compare with the parameters reversed.
   virtual int Compare( Object^ x, Object^ y ) sealed = IComparer::Compare
      return ((gcnew CaseInsensitiveComparer)->Compare( y, x ));


int main()

   // Creates and initializes a new ArrayList.
   ArrayList^ myAL = gcnew ArrayList;
   myAL->Add( "The" );
   myAL->Add( "quick" );
   myAL->Add( "brown" );
   myAL->Add( "fox" );
   myAL->Add( "jumps" );
   myAL->Add( "over" );
   myAL->Add( "the" );
   myAL->Add( "lazy" );
   myAL->Add( "dog" );

   // Displays the values of the ArrayList.
   Console::WriteLine( "The ArrayList initially contains the following values:" );
   PrintIndexAndValues( myAL );

   // Sorts the values of the ArrayList using the default comparer.
   Console::WriteLine( "After sorting with the default comparer:" );
   PrintIndexAndValues( myAL );

   // Sorts the values of the ArrayList using the reverse case-insensitive comparer.
   IComparer^ myComparer = gcnew myReverserClass;
   myAL->Sort( myComparer );
   Console::WriteLine( "After sorting with the reverse case-insensitive comparer:" );
   PrintIndexAndValues( myAL );

void PrintIndexAndValues( IEnumerable^ myList )
   int i = 0;
   IEnumerator^ myEnum = myList->GetEnumerator();
   while ( myEnum->MoveNext() )
      Object^ obj = safe_cast<Object^>(myEnum->Current);
      Console::WriteLine( "\t[{0}]:\t{1}", i++, obj );


This code produces the following output.
The ArrayList initially contains the following values:
        [0]:    The
        [1]:    quick
        [2]:    brown
        [3]:    fox
        [4]:    jumps
        [5]:    over
        [6]:    the
        [7]:    lazy
        [8]:    dog

After sorting with the default comparer:
        [0]:    brown
        [1]:    dog
        [2]:    fox
        [3]:    jumps
        [4]:    lazy
        [5]:    over
        [6]:    quick
        [7]:    the
        [8]:    The

After sorting with the reverse case-insensitive comparer:
        [0]:    the
        [1]:    The
        [2]:    quick
        [3]:    over
        [4]:    lazy
        [5]:    jumps
        [6]:    fox
        [7]:    dog
        [8]:    brown 

Universal Windows Platform
Available since 4.5
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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