Troubleshooting Exceptions: System.IndexOutOfRangeException

An IndexOutOfRangeException exception is thrown when an attempt is made to access an element of an array or collection with an index that is outside the bounds of the array or less than zero.

Associated Tips

• Make sure that the maximum index on a list is less than the list size
  The maximum index on a list must be less than the list size.

• Make sure the index is not a negative number.
  This exception will be thrown if the index is less than zero.

• Make sure data column names are correct.
  This exception may be thrown if the data column name being supplied to the DataView.Sort property is not valid. For more information, see the DataView class.

Example

Description

The following example uses a Try…Catch block to trap the IndexOutOfRangeException when index i is outside the array bounds, 0 to 3. The example displays the following:

Element at index 0: 3

Element at index 2: 5

Element at index -1: IndexOutOfRangeException caught

Element at index 4: IndexOutOfRangeException caught

Code

Module Module1

    Sub Main()
        ' The first two tests will display the value of the array element.
        IndexTest(0)
        IndexTest(2)
        ' The following two calls will display the information that
        ' an IndexOutOfRangeException was caught.
        IndexTest(-1)
        IndexTest(4)
    End Sub

    Sub IndexTest(ByVal i As Integer)
        Dim testArray() As Integer = {3, 4, 5, 6}
        Console.Write("Element at index {0}: ", i)
        Try
            Console.WriteLine(testArray(i))
        Catch ex As IndexOutOfRangeException
            Console.WriteLine("IndexOutOfRangeException caught")
        End Try
    End Sub

End Module

See Also

IndexOutOfRangeException
How to: Use the Exception Assistant
Arrays in Visual Basic