Name
LBound Function
Class
Microsoft.VisualBasic.Information
Syntax
LBound(array
[,rank
])
-
array
(required; any array) An array whose lower bound is to be determined
-
rank
(optional; Integer) The dimension whose lower bound is desired
Return Value
An Integer whose value is 0
Description
Determines the lower boundary of a specified dimension of an array. The lower boundary is the smallest subscript you can access within the specified array.
Rules at a Glance
Unless it is passed an invalid argument, the LBound function always returns 0.
If
array
is uninitialized, it generates an ArgumentNullException error when passed to the LBound function. You can prevent this by comparingarray
toNothing
, as in the following code fragment:If Not oArray Is Nothing Then
To determine the lower limit of the first dimension of an array, set
rank
to 1, set it to 2 for the second, and so on.If
rank
isn’t specified, 1 is assumed.
Programming Tips and Gotchas
Since VB.NET does not allow you to change the lower bound of an array, the LBound function would appear to be superfluous except for reasons of backward compatibility. Its continued use may be a good idea, though, in the event that a future version of VB.NET allows you to set the lower boundary of an array.
VB.NET/VB 6 Differences
Since VB 6 offers a number of ways to set the lower bound of all arrays or a specific array, the LBound function is particularly useful when iterating the elements of an array. In VB.NET, its use is a matter of choice.
See Also
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