How to implement error handling? - error-handling

Question

My AutoIt script generates an error that I want to handle. A way that any error goes to a custom function will also do. In VBA I use OnErrorGoTo, but I am unable to find something similar in AutoIt.
My Code :
Func Start()
While 1
If ProcessExists ( "Photoshop.exe" ) <> 0 Then
Sleep(5000)
Else
Local $sFile ="C:\Auto\CodeToBe\Batch\Image Process-50-2D v.2-" & $n & ".jsxbin"
Local $iPID = ShellExecute($sFile)
Sleep(10000)
$n = $n+1
EndIf
WEnd
EndFunc
An error will occur when $n exceeds the number of files in that folder. I tried this but didn't work (from the "HELP SECTION" and a forum post):
Global $iEventError = 0 ; To be checked to know if COM error occurs. Must be reset after handling.
Local $oMyError = ObjEvent("AutoIt.Error", "ErrFunc") ; Install a custom error handler
Func Start()
While 1
If ProcessExists ( "Photoshop.exe" ) <> 0 Then
Sleep(5000)
Else
Local $sFile ="C:\Auto\CodeToBe\Batch\Image Process-50-2D v.2-" & $n & ".jsxbin"
Local $iPID = ShellExecute($sFile)
If $iEventError Then
MsgBox($MB_OK, "", "There was an error on the previous line.")
$iEventError = 0 ; Reset after displaying a COM Error occurred
EndIf
Sleep(10000)
$n = $n+1
EndIf
WEnd
EndFunc
; This is my custom error handler
Func MyErrFunc()
Msgbox(0,"","ERROR GENERATED ON " & $n)
Endfunc

Answer 1

I recommend the second example because it prevents an error in the first place. However, the first example can be used as a general error checker.
Example 1
Start()
Func Start()
Local $n = 1
While 1
If ProcessExists("Photoshop.exe") <> 0 Then
Sleep(5000)
Else
Local $sFile = "C:\Auto\CodeToBe\Batch\Image Process-50-2D v.2-" & $n & ".jsxbin"
Local $iPID = ShellExecute($sFile)
If #error Then MyErrFunc(#ScriptLineNumber, #error) ;check for error
Sleep(10000)
$n = $n + 1
EndIf
WEnd
EndFunc ;==>Start
; error handler
Func MyErrFunc($iLineNumer, $iError)
$iLineNumer = $iLineNumer - 1
MsgBox(0, "", "ERROR GENERATED ON SCRIPT LINE: " & $iLineNumer & #CRLF & "ERROR CODE: " & $iError)
EndFunc ;==>MyErrFunc
Example 2
Start2()
Func Start2()
Local $n = 1
While 1
If ProcessExists("Photoshop.exe") <> 0 Then
Sleep(5000)
Else
Local $sFile = "C:\Auto\CodeToBe\Batch\Image Process-50-2D v.2-" & $n & ".jsxbin"
If FileExists($sFile) Then
Local $iPID = ShellExecute($sFile)
Sleep(10000)
Else ;handle error (you could use a function here if you wanted)
ConsoleWrite("File not found: " & $sFile & #CRLF)
EndIf
$n = $n + 1
EndIf
WEnd
EndFunc ;==>Start2

Answer 2

Try to implement error checking.
If Not FileExists(your string with the $n) Then
... abort
Else
shellexecute ...
You could use _FileListToArray() instead.

Answer 3

An error will occur when $n exceeds the number of files in that folder.
As per Documentation - Function Reference - _FileListToArray() :
Lists files and\or folders in a specified folder (Similar to using Dir with the /B Switch)
Will loop over existing filenames only (avoiding error altogether). Example:
#include <File.au3>
Global Const $g_sPathFiles = 'C:\Auto\CodeToBe\Batch\'
Global Const $g_sMaskFile = '*.jsxbin'
Global Const $g_aFile = _FileListToArray($g_sPathFiles, $g_sMaskFile, $FLTA_FILES, True)
For $i1 = 1 To $g_aFile[0]
ShellExecuteWait($g_aFile[$i1])
Next
Alternatively _FileListToArrayRec() may be used.
Related.