Error Handling Vbscript Part One
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LippertAugust 19, 200419 0 0 0 OK, enough about the Peloponnesian war -- a number of readers have asked me questions about error handling in VBScript recently, so I think I'll talk about it a bit for the next few days. Today, error handling in vbscript examples I want to very carefully describe what the error handling semantics are in the error handling in vbscript tutorial language, because there is some confusion over how exactly it works. There are two statements that affect error handling in VBScript: On vbscript error handling best practices Error Resume NextOn Error Goto 0 The meaning of the first seems clear -- if you get an error, ignore it and resume execution on the next statement. But as we'll see, there are some subtleties.
Vbscript Error Handling Line Number
But before that, what the heck is up with the second statement? The second statement turns off ‘resume next' mode if it is on. Yes, the syntax is ridiculous -- something like On Error Raise would be a whole lot more clear. But for historical purposes, this is what we're stuck with. Visual Basic has an error handling mode which VBScript does not -- VB can branch to a labeled or numbered vbscript on error continue statement. (Remember line numbers? Those were the days!) To tell VB that you no longer wish to branch to that statement, you give zero, an invalid line number. C'est super-beaucoup-de-fromage, n'est-ce pas? But we're stuck with it now. The subtlety in the "resume next" mode is best illustrated with an example. Const InvalidCall = 5Print "Global code start"Blah1Print "Global code end"Sub Blah1() On Error Resume Next Print "Blah1 Start" Blah2 Print "Blah1 End"End SubSub Blah2() Print "Blah2 Start" Err.Raise InvalidCall Print "Blah2 End"End Sub This prints out Global code startBlah1 StartBlah2 StartBlah1 EndGlobal code end Hold on a minute -- when the error happened, Blah1 had already turned ‘resume next' mode on. The next statement after the error raise is Print "Blah2 End" but that statement never got executed. What's going on? What's going on is that the error mode is on a per-procedure basis, not a global basis. (If it were on a global basis, all kinds of bad things could happen -- think about how you'd have to design a program to have consistent error handling in a world where that setting is global, and you'll see why it's per-procedure.) In this case, Blah2 gets an error. Blah2 is not in ‘resume next' mode, so it aborts itself, records t
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Vbscript On Error Resume Next
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helping each other. Join them; it only takes a minute: Sign up VBScript — Using error handling up vote 58 down vote favorite 13 I want to use VBScript to catch errors and log them (ie on error https://blogs.msdn.microsoft.com/ericlippert/2004/08/19/error-handling-in-vbscript-part-one/ "log something") then resume the next line of the script. For example, On Error Resume Next 'Do Step 1 'Do Step 2 'Do Step 3 When an error occurs on step 1, I want it to log that error (or perform other custom functions with it) then resume at step 2. Is this possible? and how can I implement it? EDIT: Can I do something like this? On Error Resume myErrCatch 'Do step 1 'Do step http://stackoverflow.com/questions/157747/vbscript-using-error-handling 2 'Do step 3 myErrCatch: 'log error Resume Next vbscript error-handling share|improve this question edited Oct 1 '08 at 14:13 asked Oct 1 '08 at 14:04 apandit 2,50111831 1 Dylan's response is about as good as VB gets in the Error handling department. This is why I always used Javascript when I could get away with it. –wcm Oct 1 '08 at 14:23 add a comment| 2 Answers 2 active oldest votes up vote 102 down vote accepted VBScript has no notion of throwing or catching exceptions, but the runtime provides a global Err object that contains the reuslts of the last operation performed. You have to explicitly check whether the Err.Number property is non-zero after each operation. On Error Resume Next DoStep1 If Err.Number <> 0 Then WScript.Echo "Error in DoStep1: " & Err.Description Err.Clear End If DoStep2 If Err.Number <> 0 Then WScript.Echo "Error in DoStop2:" & Err.Description Err.Clear End If 'If you no longer want to continue following an error after that block's completed, 'call this. On Error Goto 0 The "On Error Goto [label]" syntax is supported by Visual Basic and Visual Basic for Applications (VBA), but VBScript doesn't support this language feature so you have to use On Error Resume Next as described above. share|improve this answer edited Oct 1 '08 at 14:36 answered Oct 1 '08 at 14:11 Dyla
error handling On Error goto https://www.tutorialspoint.com/vbscript/vbscript_error_handling.htm 0 - Disable error handling Error properties: err.Number (default) err.Source err.Description Examples In the examples below - replace the 'code goes here' line with your VBScript commands. Example 1) Trap error handling an error On Error Resume Next' code goes hereIf Err.Number <> 0 Then 'error handling: WScript.Echo Err.Number & " Srce: " & Err.Source & " Desc: " & Err.Description Err.ClearEnd If Example 2) Trap an error or error handling in success On Error Resume Next' code goes hereIf Err.Number = 0 Then WScript.Echo "It worked!" Else WScript.Echo "Error:" WScript.Echo Err.Number & " Srce: " & Err.Source & " Desc: " & Err.Description Err.ClearEnd If Example 3) Trap an error On Error Resume Next' code goes hereIf Err.Number <> 0 Then ShowError("It failed") Sub ShowError(strMessage) WScript.Echo strMessage WScript.Echo Err.Number & " Srce: " & Err.Source & " Desc: " & Err.Description Err.Clear End Sub “Success is falling nine times and getting up ten” ~ Jon Bon Jovi Related: Syntax - error codes InputBox - Prompt for user input Equivalent in PowerShell: ErrorAction and $errorActionPreference © Copyright SS64.com 1999-2016 Some rights reserved
Enabling VBScript - Placement VBScript - Variables VBScript - Constants VBScript - Operators VBScript - Decisions VBScript - Loops VBScript - Events VBScript - Cookies VBScript - Numbers VBScript - Strings VBScript - Arrays VBScript - Date VBScript Advanced VBScript - Procedures VBScript - Dialog Boxes VBScript - Object Oriented VBScript - Reg Expressions VBScript - Error Handling VBScript - Misc Statements VBScript Useful Resources VBScript - Questions and Answers VBScript - Quick Guide VBScript - Useful Resources VBScript - Discussion Selected Reading Developer's Best Practices Questions and Answers Effective Resume Writing HR Interview Questions Computer Glossary Who is Who VBScript - Error Handling Advertisements Previous Page Next Page There are three types of errors in programming: (a) Syntax Errors and (b) Runtime Errors (c) Logical Errors. Syntax errors Syntax errors, also called parsing errors, occur at interpretation time for VBScript. For example, the following line causes a syntax error because it is missing a closing parenthesis: Runtime errors Runtime errors, also called exceptions, occur during execution, after interpretation. For example, the following line causes a runtime error because here syntax is correct but at runtime it is trying to call fnmultiply, which is a non-existing function: Logical errors Logic errors can be the most difficult type of errors to track down. These errors are not the result of a syntax or runtime error. Instead, they occur when you make a mistake in the logic that drives your script and you do not get the result you expected. You can not catch those errors, because it de