On Error Vb6 Example
Contents |
resources Windows Server 2012 resources Programs MSDN subscriptions Overview Benefits Administrators Students Microsoft Imagine Microsoft Student Partners ISV Startups TechRewards Events Community Magazine Forums Blogs Channel 9 Documentation APIs and reference Dev centers Samples Retired on error goto content We’re sorry. The content you requested has been removed. You’ll be auto redirected
On Error Goto Line
in 1 second. Visual Basic Language Reference Statements F-P Statements F-P Statements On Error Statement On Error Statement On Error on error exit sub Statement For Each...Next Statement For...Next Statement Function Statement Get Statement GoTo Statement If...Then...Else Statement Implements Statement Imports Statement (.NET Namespace and Type) Imports Statement (XML Namespace) Inherits Statement Interface Statement Mid Statement Module
On Error Goto 0
Statement Namespace Statement On Error Statement Operator Statement Option
Database Guide User login Username: * Password: * Request new password Home › Tutorials Error Handling In Visual Basic Level: Despite your best efforts to cover all possible contingencies, run-time errors will occur in your applications. You can and should do all you can to prevent
Vba On Error Goto 0
them, but when they happen you have to handle them. Introduction Trapping Errors at Run-Time
Vba Error Handling In Loop
Building Error Handlers Raising Your Own Errors Summary Introduction The various functions, statements, properties and methods available in Visual Basic and the components used vba error number in Visual Basic expect to deal with certain types of data and behavior in your applications. For example, the CDate() function can convert a value to a Date variable. The function is remarkably flexible in the type of information it https://msdn.microsoft.com/en-us/library/5hsw66as.aspx can accept, but it expects to receive data that it can use to derive a date. If you provide input that it can't convert, it raises error number 13 - "Type mismatch" - essentially saying "I can't handle this input data." In an application, this type of error may be a program logic error (you simply passed the wrong data) or it may be a data entry error on the part of the user (you asked for a date and http://www.vb6.us/tutorials/error-handling the user typed a name). In the first case, you need to debug the program to fix the mistake. However, there is no way for you to anticipate the behavior of the end users of the application. If the user enters data you can't handle, you need to deal with the situation. Dealing with errors at run-time is a two step process: Trap the Error Before you can deal with an error, you need to know about it. You use VB's On Error statement to setup an error trap. Handle the Error Code in your error handler may correct an error, ignore it, inform the user of the problem, or deal with it in some other way. You can examine the properties of the Err object to determine the nature of the error. Once the error has been dealt with, you use the Resume statement to return control to the regular flow of the code in the application. In addition to dealing with run-time errors, you may at times want to generate them. This is often done in class modules built as components of ActiveX server DLLs or EXEs. It is considered good programming practice to separate the user interface from the program logic as much as possible, so if a server component cannot deal with an error, it should raise the error in its client application rather than simply display an error message for the use
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 http://stackoverflow.com/questions/9035664/confused-about-error-handling-in-vb6-and-the-use-of-on-error-goto hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges http://www.developerfusion.com/code/4325/on-error-resume-next-considered-harmful/ Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Confused about Error Handling in VB6 and the use of On Error GoTo up vote 3 down vote favorite 1 I'm needing to troubleshoot some old VB6 code and on error I'm confused about the use of "On Error". In the sample below, if I surround the specific line of code I want to test with the On Error GoTo and the ErrHandler1, is that the ONLY line that's tested. Or will the divide by Zero be included if it's in the same Sub? On Error GoTo ErrHandler1 If Not Exists(BaseDirectory + "\ARCHIVE") Then _ MkDir BaseDirectory + "\ARCHIVE" ErrHandler1: Call MsgBox(Err.Number & vbCrLf & Err.Description, vbExclamation, App.Title) intValue1 on error goto = 12 intValue2 = 0 intValue3 = intValue1 / intValue Thanks. vb6 error-handling share|improve this question asked Jan 27 '12 at 15:25 JimDel 2,05453369 add a comment| 3 Answers 3 active oldest votes up vote 8 down vote accepted The divide by zero will be included and handled, and it will probably create a loop in your sample... The correct approach is like that On Error GoTo ErrHandler1 If Not Exists(BaseDirectory + "\ARCHIVE") Then _ MkDir BaseDirectory + "\ARCHIVE" On Error Goto 0 'this will un-hook you error handler intValue1 = 12 intValue2 = 0 intValue3 = intValue1 / intValue 'this will be an un-managed error Exit Sub 'this make sure that msgbox is shown only when the error happens ErrHandler1: Call MsgBox(Err.Number & vbCrLf & Err.Description, vbExclamation, App.Title) share|improve this answer answered Jan 27 '12 at 15:48 Max 4,23511426 Thanks for the explanation! –JimDel Jan 27 '12 at 16:47 +1. The documentation explains this pretty clearly... msdn.microsoft.com/en-us/library/aa266173(v=vs.60).aspx –MarkJ Jan 27 '12 at 16:53 3 Wrong - the division by zero is only handled if the MkDir operation does not thrown an error –Matt Wilko Jan 27 '12 at 16:58 @Matt: you are absolutely correct :) –Max Jan 27 '12 at 19:39 add a comment| up vote 4 down vote The division by zero is only handled if the MkDir does not cause an
Visual Basic 6 Code "On Error Resume Next" considered harmful By Palo Mraz, published on 21 Jan 2004 | Filed in Comments Visual Basic 6 SQL Server SQL As any seasoned VB programmer knows, the On Error Resume Next statement is used to check for errors the old (I might also say the C-style) way. When this statement is executed, any runtime error will be silently trapped and stored in the global Err object. We VB-ers typically use this construct to execute some "non-mission critical" code, where errors can be safely ignored. The canonical example I have seen many, many times, is the Form_Resize event handling procedure: Private Sub Form_Resize()
On Error Resume Next
' Resize the child controls on this form…
End Sub If this procedure did not contain the On Error Resume Next statement and a runtime error would occur, the application would be terminated with a nasty error message. (You do catch runtime errors in every event handling procedure, don't you?) In cases like this, the On Error Resume Next statement is quite handy, because it means less typing and more compact code. However, there are times, when this "handiness" might be very dangerous. The true danger of the On Error Resume Next statement lies in the fact that it makes it too easy to ignore the runtime errors. I have seen several cases, when ignoring runtime errors unintentionally was a recipe for disaster. Let me provide you with a real-life example taken from my own experience. Imagine a customer who had been using my application for several months and was happy with it. The application has a typical (somewhat boring:-) three-tier architecture (in the old days known as the Microsoft Windows DNA): VB6 front end; a typical forms-based application built with several 3rd party controls (GridEX, ActiveReports and AddFlow if you must know). VB6 back end; a DLL component configured to run as a COM+ application implementing the application's business logic (there is also the data access code-who writes middle-tier data access layer anyway:-). A set of T-SQL procedures for retrieving a updating the application's SQL Server 2000 database. One day the customer requested a new feature. After analyzing the request I realized that the request could be implemented just by enhancing one stored procedure. Great, I thought. I checked out the procedure from SourceSafe, fired up Query Analyzer, changed the procedure, debugged it and tested with the application on our test s