ArrayList::Sort Method (IComparer)
Updated: October 2008
Sorts the elements in the entire ArrayList using the specified comparer.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- comparer
- Type: System.Collections::IComparer
The IComparer implementation to use when comparing elements.
-or-
nullptr to use the IComparable implementation of each element.
| Exception | Condition |
|---|---|
| NotSupportedException | The ArrayList is read-only. |
If comparer is set to nullptr, this method performs a comparison sort (also called an unstable sort); that is, if two elements are equal, their order might not be preserved. In contrast, a stable sort preserves the order of elements that are equal. To perform a stable sort, you must implement a custom IComparer interface.
On average, this method is an O(n log n) operation, where n is Count; in the worst case it is an O(n^2) operation.
The following code example shows how to sort the values in an ArrayList using the default comparer and a custom comparer that reverses the sort order.
using namespace System; using namespace System::Collections; void PrintIndexAndValues( IEnumerable^ myList ); ref class myReverserClass: public IComparer { private: // 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. myAL->Sort(); 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 ); } Console::WriteLine(); } /* 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 */
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The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.