Html Vbscript On Error
Contents |
VBScript in a Nutshell by Matt Childs... Published by O'Reilly Media, Inc. VBScript in a Nutshell Preface Why This Book? Who Should Read This Book? How This Book Should Be Used How This Book Is Structured Conventions in vbscript on error goto This Book How To Contact Us I. The Basics 1. Introduction 2. Program Structure 3.
Error Handling In Vbscript Tutorial
Data Types and Variables 4. Error Handling and Debugging 5. VBScript with Active Server Pages 6. Programming Outlook Forms 7. Windows Script Host vbscript on error exit 8. VBScript with Internet Explorer II. Reference 9. The Language Reference III. Appendixes A. Language Elements by Category B. VBScript Constants C. Operators Index Colophon Error Handling Error handling does not involve finding errors in your scripts. Instead,
Vbscript Error Handling Best Practices
use error handling techniques to allow your program to continue executing even though a potentially fatal error has occurred. Ordinarily, all runtime errors that are generated by the VBScript engine are fatal, since execution of the current script is halted when the error occurs. Error handling allows you to inform the user of the problem and either halt execution of the program or, if it is prudent, continue executing the program.The On Error Resume Next StatementThere are vbscript error line number two main elements to error handling in VBScript. The first is the On Error statement, which informs the VBScript engine of your intention to handle errors yourself, rather than to allow the VBScript engine to display a typically uninformative error message and halt the program. This is done by inserting a statement like the following at the start of a procedure:On Error Resume NextThis tells the VBScript engine that, should an error occur, you want it to continue executing the program starting with the line of code which directly follows the line in which the error occurred. For example, in the simple WSH script:On Error Resume Next x = 10 y = 0 z = x / y Alert za “Cannot divide by Zero” error is generated on the fourth line of code because the value of y is 0. But because you’ve placed the On Error statement in line 1, program execution continues with line 5. The problem with this is that when an error is generated, the user is unaware of it; the only indication that an error has occurred is the blank Alert box (from line 5) that’s displayed for the user.TipA particular On Error statement is valid until another On Error statement in the line of execution is encountered. This means that if Function A contains an On Error statement, and Function A calls
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On Error Resume Next Vbscript W3schools
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If Err.number 0 Then
auto redirected in 1 second. ActiveX Data Objects (ADO) Error Handling Handling Errors In Other Languages Handling Errors In Other vbscript error message Languages Handling Errors in VBScript Handling Errors in VBScript Handling Errors in VBScript Handling Errors in VBScript Handling Errors in Visual C++ Handline Errors in Visual J++ Handling Errors in JScript TOC https://www.safaribooksonline.com/library/view/vbscript-in-a/1565927206/ch04s02.html Collapse the table of content Expand the table of content This documentation is archived and is not being maintained. This documentation is archived and is not being maintained. Handling Errors in VBScript There is little difference between the methods used in Visual Basic and those used with VBScript. The primary difference is that VBScript does not support the concept of error handling by continuing execution at https://msdn.microsoft.com/en-us/library/ms675540(v=vs.85).aspx a label. In other words, you cannot use On Error GoTo in VBScript. Instead, use On Error Resume Next and then check both Err.Number and the Count property of the Errors collection, as shown in the following example: Copy
Error Handling Example (VBScript)
<% Dim cnn1 Dim errLoop Dim strError On Error Resume Next ' Intentionally trigger an error. Set cnn1 = Server.CreateObject("ADODB.Connection") cnn1.Open "nothing" If cnn1.Errors.Count > 0 Then ' Enumerate Errors collection and display ' properties of each Error object. For Each errLoop In cnn1.Errors strError = "Error #" & errLoop.Number & "" & _ " " & errLoop.Description & "
" & _ " (Source: " & errLoop.Source & ")" & "
" & _ " (SQL State: " & errLoop.SQLState & ")" & "
" & _ " (NativeError: " & errLoop.NativeError & ")" & "
" If errLoop.HelpFile = "" Then strError = strError & _ " No Help file available" & _ "
" Else strError = strError & _ " (HelpFile: " & errLoop.HelpFile & ")" & "
" & _ " (HelpContext: " & errLoop.HelpCont
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about hiring http://stackoverflow.com/questions/2202869/what-does-the-on-error-resume-next-statement-do developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up What does the “On Error Resume Next” statement do? up vote 41 down vote favorite 4 I came to some VBScript examples, and I saw the statement On Error Resume Next basically on error at the beginning of the script. What does it do? vbscript error-handling share|improve this question edited Feb 4 '10 at 20:42 Helen 18.3k44174 asked Feb 4 '10 at 20:18 omar 3,359114280 4 It is a very powerful, but dangerous bit of syntax. Be very cautious using it. –Nate Feb 4 '10 at 20:22 2 It makes more sense now. After some functions that can end up in error. They have a function called checkError after them. –omar vbscript on error Feb 4 '10 at 20:37 add a comment| 6 Answers 6 active oldest votes up vote 56 down vote accepted It basically tells the program when you encounter an error just continue at the next line. share|improve this answer answered Feb 4 '10 at 20:19 David 2,2401522 add a comment| up vote 24 down vote It's worth noting that even when On Error Resume Next is in effect, the Err object is still populated when an error occurs, so you can still do C-style error handling. On Error Resume Next DangerousOperationThatCouldCauseErrors If Err Then WScript.StdErr.WriteLine "error " & Err.Number WScript.Quit 1 End If On Error GoTo 0 share|improve this answer answered Feb 5 '10 at 15:49 Tmdean 6,4902645 add a comment| up vote 19 down vote When an error occurs, the execution will continue on the next line without interrupting the script. share|improve this answer answered Feb 4 '10 at 20:19 Pierre-Alain Vigeant 13.7k44388 add a comment| up vote 8 down vote It means, when an error happens on the line, it is telling vbscript to continue execution without aborting the script. Sometimes, the On Error follows the Goto label to alter the flow of execution, something like this in a Sub code block, now you know why and how the usage of GOTO can result in spaghetti code: Sub MySubRoutine() On Error Goto ErrorHandler REM VB code... REM More VB Code... Exit_MySubRoutine: REM Disable