Variables
I was looking at an aged code and I started rearranging it a bit.
Unfortunately, re-arranged, it stopped working.
I took a night’s sleep.
Come the next day, less tired and wearied, I went back at it.
Thankfully, I had made a backup and had it tucked away.
Studying the saved code, I found out that the original code had set a couple of variables to values other than their default values.
Compiler Warnings
Once I arrived back at a working code, it was time to clear the compiler warnings.
The specific compiler warning that will be addressed in this post reads:
Textual
Variable ‘stringArray’ is used before it has been assigned a value. A null reference exception could result at runtime
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Code
Original
Code
Imports System
Public Module Module1
Public Sub Main()
Call handleStringArray
End Sub
private Function handleStringArray()
Dim stringArray() as String
Dim iNumberofElements as Integer
Try
For i = 0 to 100
'ReDim Preserve stringArray(i)
Next
iNumberofElements = stringArray.length
Catch ex As Exception
Console.WriteLine("Exception :- " + ex.Message)
End Try
return ( iNumberofElements )
End Function
End Module
Revision
Outline
- Declaration without initialization
- Dim stringArray() as String
- Declarations with initialization
- Dim stringArray(-1) as String
- Dim stringArray() as String = New String(-1) {}
Code
Imports System
Public Module Module1
Public Sub Main()
Call handleStringArray
End Sub
private Function handleStringArray()
'Dim stringArray() as String
Dim stringArray(-1) as String
Dim iNumberofElements as Integer
Try
For i = 0 to 100
'ReDim Preserve stringArray(i)
Next
iNumberofElements = stringArray.length
Catch ex As Exception
Console.WriteLine("Exception :- " + ex.Message)
End Try
return ( iNumberofElements )
End Function
End Module
Special Recognition
.Net Perls ( Sam Allen )
Array Vb.Net
( this section is taking verbatim from .Net Perls )
Empty Array
How does one create an empty array in VB.NET? We specify the maximum index -1 when we declare the array—this means zero elements.
Length
Length To test for an empty array, use an if-statement and access the Length property, comparing it against 0.
Code
Module Module1
Sub Main()
' Create an empty array.
Dim array(-1) As Integer
' Test for empty array.
If array.Length = 0 Then
Console.WriteLine("ARRAY IS EMPTY")
End If
End Sub
End Module
Stack Overflow
Commendation
- Bjørn-Roger Kringsjå
- Turn Option Strict On
- Force you from creating functions like Function MyArray() As Surprise, and functions that should have been a Sub
- Turn Option Strict On
- Meta-Knight
- Don’t surround your code with an empty try-catch
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Learning in the Open 