System Namespace   Array Class

---

Searches for the specified object and returns the index of the first occurrence within the section of the one-dimensional Array that starts at the specified index and contains the specified number of elements.

[ VB ]
<Serializable>
Overloads Public Shared Function IndexOf ( _
   ByVal array As Array, _
   ByVal value As Object, _
   ByVal startIndex As Integer, _
   ByVal count As Integer _
) As Integer

[ C# ]
[Serializable]
public static int IndexOf (
   Array array,
   object value,
   int startIndex,
   int count
);

[ C++ ]
[Serializable]
public: static int IndexOf (
   Array* array,
   Object* value,
   int startIndex,
   int count
);

[JScript ]
public Serializable
static function IndexOf (
   array : Array,
   value : Object,
   startIndex : int,
   count : int
) : int;

array

The one-dimensional Array to search.

value

The object to locate in array.

startIndex

The starting index of the search.

count

The number of elements in the section to search.

The index of the first occurrence of value within the section of array that starts at startIndex and contains the number of elements specified in count, if found; otherwise, the lower bound of the array - 1.

Exception Type	Condition
ArgumentNullException	array is a null reference ( Nothing in Visual Basic ).
ArgumentOutOfRangeException	startIndex is outside the range of valid indexes for array. -or- count is less than zero. -or- startIndex and count do not specify a valid section in array.
RankException	array is multidimensional.

The one-dimensional Array is searched forward starting at startIndex and ending at startIndex + count- 1.

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.

The following code example shows how to determine the index of the first occurrence of a specified element.

[ VB ] 
Imports System
Imports Microsoft.VisualBasic

Public Class SamplesArray    
    
    Public Shared Sub Main ( ) 
        
        ' Creates and initializes a new Array with three elements of
        ' the same value.
        Dim myArray As Array = Array.CreateInstance ( GetType ( String ) , 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.
        Response.WriteLine ( "The Array contains the following values:" ) 
        PrintIndexAndValues ( myArray ) 
        
        ' Searches for the first occurrence of the duplicated value.
        Dim myString As String = "the"
        Dim myIndex As Integer = Array.IndexOf ( myArray, myString ) 
        Response.WriteLine ( "The first occurrence of ""{0}"" is at index {1}.", _
           myString, myIndex ) 
        
        ' Searches for the first occurrence of the duplicated value in the last
        ' section of the Array.
        myIndex = Array.IndexOf ( myArray, myString, 4 ) 
        Response.WriteLine ( "The first occurrence of ""{0}"" between index 4 " _
           + "and the end is at index {1}.", myString, myIndex ) 
        
        ' Searches for the first occurrence of the duplicated value in a section
        ' of the Array.
        myIndex = Array.IndexOf ( myArray, myString, 6, 5 ) 
        Response.WriteLine ( "The first occurrence of ""{0}"" between index 6 " _
           + "and index 10 is at index {1}.", myString, myIndex ) 
    End Sub
    
    
    Public Shared Sub PrintIndexAndValues ( myArray As Array ) 
        Dim i As Integer
        For i = myArray.GetLowerBound ( 0 ) To myArray.GetUpperBound ( 0 ) 
            Response.WriteLine ( ControlChars.Tab + "[{0}]:" + ControlChars.Tab _
               + "{1}", i, myArray.GetValue ( i ) ) 
        Next i
    End Sub
End Class

' This code produces the following output.
' 
' The Array 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 first occurrence of "the" is at index 0.
' The first occurrence of "the" between index 4 and the end is at index 6.
' The first occurrence of "the" between index 6 and index 10 is at index 6. 

[ C# ] 
using System;
public class SamplesArray  {

   public static void Main ( )  {

      // Creates and initializes a new Array with three elements of the same value.
      Array myArray=Array.CreateInstance ( typeof ( String ) , 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.
      Response.WriteLine ( "The Array contains the following values:" );
      PrintIndexAndValues ( myArray );

      // Searches for the first occurrence of the duplicated value.
      String myString = "the";
      int myIndex = Array.IndexOf ( myArray, myString );
      Response.WriteLine ( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );

      // Searches for the first occurrence of the duplicated value in the last section of the Array.
      myIndex = Array.IndexOf ( myArray, myString, 4 );
      Response.WriteLine ( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );

      // Searches for the first occurrence of the duplicated value in a section of the Array.
      myIndex = Array.IndexOf ( myArray, myString, 6, 5 );
      Response.WriteLine ( "The first occurrence of \"{0}\" between index 6 and index 10 is at index {1}.", myString, myIndex );
   }


   public static void PrintIndexAndValues ( Array myArray )  {
      for ( int i = myArray.GetLowerBound ( 0 ); i <= myArray.GetUpperBound ( 0 ); i++ ) 
         Response.WriteLine ( "\t[{0}]:\t{1}", i, myArray.GetValue ( i ) );
   }
}
/*
This code produces the following output.

The Array 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 first occurrence of "the" is at index 0.
The first occurrence of "the" between index 4 and the end is at index 6.
The first occurrence of "the" between index 6 and index 10 is at index 6.
*/

[JScript ] 
import System;

// Creates and initializes a new Array with three elements of the same value.
var myArray : System.Array = System.Array.CreateInstance ( System.String, 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.
Response.WriteLine ( "The Array contains the following values:" );
PrintIndexAndValues ( myArray );

// Searches for the first occurrence of the duplicated value.
var myString : String = "the";
var myIndex : int = System.Array.IndexOf ( myArray, myString );
Response.WriteLine ( "The first occurrence of \"{0}\" is at index {1}.", myString, myIndex );

// Searches for the first occurrence of the duplicated value in the last section of the Array.
myIndex = System.Array.IndexOf ( myArray, myString, 4 );
Response.WriteLine ( "The first occurrence of \"{0}\" between index 4 and the end is at index {1}.", myString, myIndex );

// Searches for the first occurrence of the duplicated value in a section of the Array.
myIndex = System.Array.IndexOf ( myArray, myString, 6, 5 );
Response.WriteLine ( "The first occurrence of \"{0}\" between index 6 and index 10 is at index {1}.", myString, myIndex );
 
 
function PrintIndexAndValues ( myArray : System.Array  )  {
   for ( var i : int = myArray.GetLowerBound ( 0 ); i <= myArray.GetUpperBound ( 0 ); i++ ) 
      Response.WriteLine ( "\t[{0}]:\t{1}", i, myArray.GetValue ( i ) );
}
 
 /*
 This code produces the following output.
 
 The Array 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 first occurrence of "the" is at index 0.
 The first occurrence of "the" between index 4 and the end is at index 6.
 The first occurrence of "the" between index 6 and index 10 is at index 6.
 */

Array Members   Array.IndexOf Overload List   LastIndexOf

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