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11/18/2011

Information.UBound Method

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Returns the highest available subscript for the indicated dimension of an array.

Namespace: Microsoft.VisualBasic
Assembly: Microsoft.VisualBasic (in Microsoft.VisualBasic.dll)

Syntax

'Declaration
Public Shared Function UBound ( _
    Array As Array, _
    Rank As Integer _
) As Integer

public static int UBound(
    Array Array,
    int Rank
)

Parameters

Array
Type: System.Array
Required. Array of any data type. The array in which you want to find the highest possible subscript of a dimension.

Rank
Type: System.Int32
Optional. Integer. The dimension for which the highest possible subscript is to be returned. Use 1 for the first dimension, 2 for the second, and so on. If Rank is omitted, 1 is assumed.

Return Value

Type: System.Int32
Integer . The highest value the subscript for the specified dimension can contain. If Array has only one element, UBound returns 0. If Array has no elements, for example if it is a zero-length string, UBound returns -1.

Remarks

Since array subscripts start at 0, the length of a dimension is greater by one than the highest available subscript for that dimension.

For an array with the following dimensions, UBound returns the values in the following table:

Dim a(100, 5, 4) As Byte

Call to UBound	Return value
UBound(a, 1)	100
UBound(a, 2)	5
UBound(a, 3)	4

You can use UBound to determine the total number of elements in an array, but you must adjust the value it returns to account for the fact that the subscripts start at 0. The following example calculates the total size of the array a in the preceding example:

Dim total As Integer
total = (UBound(A, 1) + 1) * (UBound(A, 2) + 1) * (UBound(A, 3) + 1)

The value calculated for total is 3030, which is 101 * 6 * 5.

Examples

The following example uses the UBound function to determine the highest available subscript for the indicated dimension of an array.

Dim highest, bigArray(10, 15, 20), littleArray(6) As Integer
highest = UBound(bigArray, 1)
highest = UBound(bigArray, 3)
highest = UBound(littleArray)
' The three calls to UBound return 10, 20, and 6 respectively.

Version Information

Silverlight

Supported in: 5, 4, 3

Platforms

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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