Array.GetLowerBound Method (Int32)
Gets the index of the first element of the specified dimension in the array.
Assembly: mscorlib (in mscorlib.dll)
Parameters
- dimension
-
Type:
System.Int32
A zero-based dimension of the array whose starting index needs to be determined.
Return Value
Type: System.Int32The index of the first element of the specified dimension in the array.
| Exception | Condition |
|---|---|
| IndexOutOfRangeException |
GetLowerBound(0) returns the starting index of the first dimension of the array, and GetLowerBound(Rank - 1) returns the starting index of the last dimension of the array.
The GetLowerBound method always returns a value that indicates the index of the lower bound of the array, even if the array is empty.
Note that, although most arrays in the .NET Framework are zero-based (that is, the GetLowerBound method returns zero for each dimension of an array), the .NET Framework does support arrays that are not zero-based. Such arrays can be created with the CreateInstance(Type, Int32(), Int32()) method, and can also be returned from unmanaged code.
This method is an O(1) operation.
The following example uses the GetLowerBound and GetUpperBound methods to display the bounds of a one-dimensional and two-dimensional array and to display the values of their array elements.
Public Module Example Public Sub Main() ' Create a one-dimensional integer array. Dim integers() As Integer = { 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 } ' Get the upper and lower bound of the array. Dim upper As Integer = integers.GetUpperBound(0) Dim lower As Integer = integers.GetLowerBound(0) Console.WriteLine("Elements from index {0} to {1}:", lower, upper) ' Iterate the array. For ctr As Integer = lower To upper Console.Write("{0}{1}{2}", If(ctr = lower, " ", ""), integers(ctr), If(ctr < upper, ", ", vbCrLf)) Next Console.WriteLine() ' Create a two-dimensional integer array. Dim integers2d(,) As Integer = {{2, 4}, {3, 9}, {4, 16}, {5, 25}, {6, 36}, {7, 49}, {8, 64}, {9, 81} } ' Get the number of dimensions. Dim rank As Integer = integers2d.Rank Console.WriteLine("Number of dimensions: {0}", rank) For ctr As Integer = 0 To integers2d.Rank - 1 Console.WriteLine(" Dimension {0}: from {1} to {2}", ctr, integers2d.GetLowerBound(ctr), integers2d.GetUpperBound(ctr)) Next ' Iterate the 2-dimensional array and display its values. Console.WriteLine(" Values of array elements:") For outer = integers2d.GetLowerBound(0) To integers2d.GetUpperBound(0) For inner = integers2d.GetLowerBound(1) To integers2d.GetUpperBound(1) Console.WriteLine(" {3}{0}, {1}{4} = {2}", outer, inner, integers2d.GetValue(outer, inner), "{", "}") Next Next End Sub End Module ' The example displays the following output. ' Elements from index 0 to 9: ' 2, 4, 6, 8, 10, 12, 14, 16, 18, 20 ' ' Number of dimensions: 2 ' Dimension 0: from 0 to 7 ' Dimension 1: from 0 to 1 ' Values of array elements: ' {0, 0} = 2 ' {0, 1} = 4 ' {1, 0} = 3 ' {1, 1} = 9 ' {2, 0} = 4 ' {2, 1} = 16 ' {3, 0} = 5 ' {3, 1} = 25 ' {4, 0} = 6 ' {4, 1} = 36 ' {5, 0} = 7 ' {5, 1} = 49 ' {6, 0} = 8 ' {6, 1} = 64 ' {7, 0} = 9 ' {7, 1} = 81
Available since 8
.NET Framework
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1