Array.GetLength Method (System)

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.NET Framework Class Library
Array.GetLength Method

Gets a 32-bit integer that represents the number of elements in the specified dimension of the Array.

Namespace:  System
Assembly:  mscorlib (in mscorlib.dll)
Syntax
Visual Basic
Public Function GetLength ( _
	dimension As Integer _
) As Integer
C#
public int GetLength(
	int dimension
)
Visual C++
public:
int GetLength(
	int dimension
)
F#
member GetLength : 
        dimension:int -> int

Parameters

dimension
Type: System.Int32
A zero-based dimension of the Array whose length needs to be determined.

Return Value

Type: System.Int32
A 32-bit integer that represents the number of elements in the specified dimension.
Exceptions
Exception Condition
IndexOutOfRangeException

dimension is less than zero.

-or-

dimension is equal to or greater than Rank.
Remarks

An example of GetLength is GetLength(0), which returns the number of elements in the first dimension of the Array.

This method is an O(1) operation.

Examples

The following example shows how to use GetLength to display the dimensions of two arrays with different ranks.

Visual Basic

Imports System

Public Class SamplesArray
    Public Shared Sub Main()
        ' make a single dimension array
        Dim MyArray1 As Array = Array.CreateInstance(GetType(Integer), 5)

        ' make a 3 dimensional array
        Dim MyArray2 As Array = Array.CreateInstance(GetType(Integer), 5, 3, 2)

        ' make an array container
        Dim BossArray As Array = Array.CreateInstance(GetType(Array), 2)
        BossArray.SetValue(MyArray1, 0)
        BossArray.SetValue(MyArray2, 1)

        Dim i As Integer = 0
        Dim j As Integer
        Dim rank As Integer
        For Each anArray As Array In BossArray
            rank = anArray.Rank
            If rank > 1
                Console.WriteLine("Lengths of {0:d} dimension array[{1:d}]", rank, i)
                ' show the lengths of each dimension
                For j = 0 To rank - 1
                    Console.WriteLine("    Length of dimension({0:d}) = {1:d}", j, anArray.GetLength(j))
                Next j
            Else
                Console.WriteLine("Lengths of single dimension array[{0:d}]", i)
            End If
            ' show the total length of the entire array or all dimensions
            Console.WriteLine("    Total length of the array = {0:d}", anArray.Length)
            Console.WriteLine()
            i = i + 1
        Next anArray
    End Sub
End Class

'This code produces the following output:
'
'Lengths of single dimension array[0]
'    Total length of the array = 5
'
'Lengths of 3 dimension array[1]
'    Length of dimension(0) = 5
'    Length of dimension(1) = 3
'    Length of dimension(2) = 2
'    Total length of the array = 30
C#

using System;

public class SamplesArray
{
    public static void Main()
    {
        // make a single dimension array
        Array MyArray1 = Array.CreateInstance(typeof(int), 5);

        // make a 3 dimensional array
        Array MyArray2 = Array.CreateInstance(typeof(int), 5, 3, 2);

        // make an array container
        Array BossArray = Array.CreateInstance(typeof(Array), 2);
        BossArray.SetValue(MyArray1, 0);
        BossArray.SetValue(MyArray2, 1);

        int i = 0, j, rank;
        foreach (Array anArray in BossArray)
        {
            rank = anArray.Rank;
            if (rank > 1)
            {
                Console.WriteLine("Lengths of {0:d} dimension array[{1:d}]", rank, i);
                // show the lengths of each dimension
                for (j = 0; j < rank; j++)
                {
                    Console.WriteLine("    Length of dimension({0:d}) = {1:d}", j, anArray.GetLength(j));
                }
            }
            else
            {
                Console.WriteLine("Lengths of single dimension array[{0:d}]", i);
            }
            // show the total length of the entire array or all dimensions
            Console.WriteLine("    Total length of the array = {0:d}", anArray.Length);
            Console.WriteLine();
            i++;
        }
    }
}

/*
This code produces the following output:

Lengths of single dimension array[0]
    Total length of the array = 5

Lengths of 3 dimension array[1]
    Length of dimension(0) = 5
    Length of dimension(1) = 3
    Length of dimension(2) = 2
    Total length of the array = 30
*/
Visual C++

using namespace System;

public ref class SamplesArray
{
public:
    static void Main()
    {
        // make a single dimension array
        Array^ MyArray1 = Array::CreateInstance(int::typeid, 5);

        // make a 3 dimensional array
        Array^ MyArray2 = Array::CreateInstance(int::typeid, 5, 3, 2);

        // make an array container
        Array^ BossArray = Array::CreateInstance(Array::typeid, 2);
        BossArray->SetValue(MyArray1, 0);
        BossArray->SetValue(MyArray2, 1);

        int i = 0, j, rank;
        for each (Array^ anArray in BossArray)
        {
            rank = anArray->Rank;
            if (rank > 1)
            {
                Console::WriteLine("Lengths of {0:d} dimension array[{1:d}]", rank, i);
                // show the lengths of each dimension
                for (j = 0; j < rank; j++)
                {
                    Console::WriteLine("    Length of dimension({0:d}) = {1:d}", j, anArray->GetLength(j));
                }
            }
            else
            {
                Console::WriteLine("Lengths of single dimension array[{0:d}]", i);
            }
            // show the total length of the entire array or all dimensions
            Console::WriteLine("    Total length of the array = {0:d}", anArray->Length);
            Console::WriteLine();
            i++;
        }
    }
};

int main()
{
    SamplesArray::Main();
}

/*
This code produces the following output:

Lengths of single dimension array[0]
    Total length of the array = 5

Lengths of 3 dimension array[1]
    Length of dimension(0) = 5
    Length of dimension(1) = 3
    Length of dimension(2) = 2
    Total length of the array = 30
*/
Version Information

.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library
Platforms

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.
See Also

Reference

Array Class
System Namespace
Length
GetLongLength
ICollection.Count
Rank