Array::LastIndexOf Method (Array, Object)
Searches for the specified object and returns the index of the last occurrence within the entire one-dimensional Array.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- array
- Type: System::Array
The one-dimensional Array to search.
- value
- Type: System::Object
The object to locate in array.
Return Value
Type: System::Int32The index of the last occurrence of value within the entire array, if found; otherwise, the lower bound of the array minus 1.
| Exception | Condition |
|---|---|
| ArgumentNullException | array is nullptr. |
| RankException | array is multidimensional. |
The one-dimensional Array is searched backward starting at the last element and ending at the first element.
The elements are compared to the specified value using the Object::Equals method. If the element type is a nonintrinsic (user-defined) type, the Equals implementation of that type is used.
Since most arrays will have a lower bound of zero, this method would generally return –1 when value is not found. In the rare case that the lower bound of the array is equal to Int32::MinValue and value is not found, this method returns Int32::MaxValue, which is System.Int32.MinValue - 1.
This method is an O(n) operation, where n is the Length of array.
In the .NET Framework version 2.0, this method uses the Equals and CompareTo methods of the Array to determine whether the Object specified by the value parameter exists. In the earlier versions of the .NET Framework, this determination was made by using the Equals and CompareTo methods of the value Object itself.
CompareTo methods of the item parameter on the objects in the collection.
The following code example shows how to determine the index of the last occurrence of a specified element in an array.
using namespace System; void PrintIndexAndValues( Array^ myArray ); void main() { // Creates and initializes a new Array instance with three elements of the same value. Array^ myArray = Array::CreateInstance( String::typeid, 12 ); myArray->SetValue( "the", 0 ); myArray->SetValue( "quick", 1 ); myArray->SetValue( "brown", 2 ); myArray->SetValue( "fox", 3 ); myArray->SetValue( "jumped", 4 ); myArray->SetValue( "over", 5 ); myArray->SetValue( "the", 6 ); myArray->SetValue( "lazy", 7 ); myArray->SetValue( "dog", 8 ); myArray->SetValue( "in", 9 ); myArray->SetValue( "the", 10 ); myArray->SetValue( "barn", 11 ); // Displays the values of the Array. Console::WriteLine( "The Array instance contains the following values:" ); PrintIndexAndValues( myArray ); // Searches for the last occurrence of the duplicated value. String^ myString = "the"; int myIndex = Array::LastIndexOf( myArray, myString ); Console::WriteLine( "The last occurrence of \"{0}\" is at index {1}.", myString, myIndex ); // Searches for the last occurrence of the duplicated value in the first section of the Array. myIndex = Array::LastIndexOf( myArray, myString, 8 ); Console::WriteLine( "The last occurrence of \"{0}\" between the start and index 8 is at index {1}.", myString, myIndex ); // Searches for the last occurrence of the duplicated value in a section of the Array. // Note that the start index is greater than the end index because the search is done backward. myIndex = Array::LastIndexOf( myArray, myString, 10, 6 ); Console::WriteLine( "The last occurrence of \"{0}\" between index 5 and index 10 is at index {1}.", myString, myIndex ); } void PrintIndexAndValues( Array^ myArray ) { for ( int i = myArray->GetLowerBound( 0 ); i <= myArray->GetUpperBound( 0 ); i++ ) Console::WriteLine( "\t[{0}]:\t{1}", i, myArray->GetValue( i ) ); } /* This code produces the following output. The Array instance contains the following values: [0]: the [1]: quick [2]: brown [3]: fox [4]: jumped [5]: over [6]: the [7]: lazy [8]: dog [9]: in [10]: the [11]: barn The last occurrence of "the" is at index 10. The last occurrence of "the" between the start and index 8 is at index 6. The last occurrence of "the" between index 5 and index 10 is at index 10. */
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.