IndexOf Method (Array, Object, Int32)

Article
01/16/2013

[This documentation is for preview only, and is subject to change in later releases. Blank topics are included as placeholders.]

Searches for the specified object and returns the index of the first occurrence within the range of elements in the one-dimensional Array that extends from the specified index to the last element.

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

Syntax

'Declaration
Public Shared Function IndexOf ( _
    array As Array, _
    value As Object, _
    startIndex As Integer _
) As Integer

public static int IndexOf(
    Array array,
    Object value,
    int startIndex
)

public:
static int IndexOf(
    Array^ array, 
    Object^ value, 
    int startIndex
)

static member IndexOf : 
        array:Array * 
        value:Object * 
        startIndex:int -> int

public static function IndexOf(
    array : Array, 
    value : Object, 
    startIndex : int
) : int

Parameters

array
Type: System. . :: . .Array
The one-dimensional Array to search.

value
Type: System. . :: . .Object
The object to locate in array.

startIndex
Type: System. . :: . .Int32
The starting index of the search. 0 (zero) is valid in an empty array.

Return Value

Type: System. . :: . .Int32
The index of the first occurrence of value within the range of elements in array that extends from startIndex to the last element, if found; otherwise, the lower bound of the array minus 1.

Exceptions

Exception	Condition
ArgumentNullException	array is null Nothing nullptr unit a null reference (Nothing in Visual Basic) .
ArgumentOutOfRangeException	startIndex is outside the range of valid indexes for array.
RankException	array is multidimensional.

Remarks

The one-dimensional Array is searched forward starting at startIndex and ending at the last 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.

Passing the Length of the array as the startindex will result in a return value of -1, while values greater than Length will raise an ArgumentOutOfRangeException.

This method is an O(n) operation, where n is the number of elements from startIndex to the end of array.

.NET Framework Security

Full trust for the immediate caller. This member cannot be used by partially trusted code. For more information, see dd66cd4c-b087-415f-9c3e-94e3a1835f74.

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