Excel Vba On Error Goto Function
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three flavors: compiler errors such as undeclared variables that prevent your code from compiling; user data entry error such as a user excel vba on error goto next loop entering a negative value where only a positive number is acceptable; and excel vba on error goto line run time errors, that occur when VBA cannot correctly execute a program statement. We will concern ourselves here
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only with run time errors. Typical run time errors include attempting to access a non-existent worksheet or workbook, or attempting to divide by zero. The example code in this
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article will use the division by zero error (Error 11) when we want to deliberately raise an error. Your application should make as many checks as possible during initialization to ensure that run time errors do not occur later. In Excel, this includes ensuring that required workbooks and worksheets are present and that required names are defined. The excel vba on error goto line number more checking you do before the real work of your application begins, the more stable your application will be. It is far better to detect potential error situations when your application starts up before data is change than to wait until later to encounter an error situation. If you have no error handling code and a run time error occurs, VBA will display its standard run time error dialog box. While this may be acceptable, even desirable, in a development environment, it is not acceptable to the end user in a production environment. The goal of well designed error handling code is to anticipate potential errors, and correct them at run time or to terminate code execution in a controlled, graceful method. Your goal should be to prevent unhandled errors from arising. A note on terminology: Throughout this article, the term procedure should be taken to mean a Sub, Function, or Property procedure, and the term exit statement should be taken to mean Exit Sub, Exit Function, or Exit Property. The term end s
generally put more focus on the coding part and getting the desired result but during this process we forget an important thing i.e. Error handling. Error handling is an important part of every code and VBA On Error Statement
Excel Vba On Error Goto 0
is an easy way for handling unexpected exceptions in Excel Macros. A well written macro is excel vba on error goto errorhandler one that includes proper exception handling routines to catch and tackle every possible error. Error handling is important because in case of any unexpected on error exit sub vba exceptions your code doesn’t break. Even if any fatal unexpected error occurs in the code then also you should ensure that the code should terminate gracefully. Definition of VBA On Error Statement: On Error statement instructs VBA Compiler, what http://www.cpearson.com/excel/errorhandling.htm to do in case any runtime exception are thrown. Syntax of On Error Statement: Basically there are three types of On Error statement: On Error Goto 0 On Error Resume Next On Error Goto
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 developers or http://stackoverflow.com/questions/19042604/vba-excel-error-handling-especially-in-functions-professional-excel-developm 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 VBA Excel Error Handling - especially in functions - Professional Excel Development Style up vote 5 down vote favorite 4 I got the book "Professional Excel Development" by Rob Bovey and it is opening up my on error eyes. I am refitting my code with error handling. However, there is a lot I don't understand. I especially need to know how to correctly use it in functions. I use Bovey's rethrow version of the error handler (at bottom). When I started, I was using the basic boolean (non-rethrow) method and turned my subroutines into boolean functions. (P.S. I am switching back to the boolean method based on the answer.) I need guidance on how to fit functions into this excel vba on scheme. I want them to return their real values (a string or double, e.g., or -1 if they fail in some cases) so I can nest them in other functions and not just return an error handling boolean. This is what a typical subroutine call to bDrawCellBorders(myWS) would look like within an entry point. Sub calls seem to be working well. (I.e. it is a subroutine that was turned into a function only so it can return a boolean to the error handling scheme.) Sub UpdateMe() ' Entry Point Const sSOURCE As String = "UpdateMe()" On Error GoTo ErrorHandler Set myWS = ActiveCell.Worksheet Set myRange = ActiveCell myWS.Unprotect ' lots of code If Not bDrawCellBorders(myWS) Then ERR.Raise glHANDLED_ERROR ' Call subroutine ' lots of code ErrorExit: On Error Resume Next Application.EnableEvents = True myWS.Protect AllowFormattingColumns:=True Exit Sub ErrorHandler: If bCentralErrorHandler(msMODULE, sSOURCE,,True) Then ' Call as Entry Point Stop Resume Else Resume ErrorExit End If End Sub However, I don't know how to extend this to real functions. This is based off an example in the book that was drawn up for a subroutine, and I just switched it to a function. Questions: * How do I call it? Is it simply like x = sngDoSomeMath(17) * Will its error handling function properly? * Where is the right place or places to call the error handling routine with bReThrow=true? Public Function sngDoSomeMath(ByVal iNum As Integer) As Single Dim sngResult As Single Const sSO