Error Handling Techniques In Vba
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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 entering a negative value where only a positive number is acceptable; and run time errors, that occur when VBA cannot correctly execute a program statement. vba error handling best practices We will concern ourselves here only with run time errors. Typical run time errors include attempting vba error handling loop to access a non-existent worksheet or workbook, or attempting to divide by zero. The example code in this article will use the division by zero
Vba Error Handling Function
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
Vba Error Handling Exit Sub
worksheets are present and that required names are defined. The 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 vba access error handling 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 statement should be taken to mean End Sub , End Function, End Property, or just End. The On Error Statement The heart of error handling in VBA is the On Error statement. This statement instructs VBA what to do when an run time error is encountered. The On Error statement takes three forms. On Error Goto 0 On Error Resume Next On Error Goto
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Vba Error Handling Display Message
company Business Learn more about hiring developers or posting ads with us Stack Overflow vba error handling line number Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 4.7 vba error handling in do while loop 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 http://www.cpearson.com/excel/errorhandling.htm 4 I got the book "Professional Excel Development" by Rob Bovey and it is opening up my 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 http://stackoverflow.com/questions/19042604/vba-excel-error-handling-especially-in-functions-professional-excel-developm 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 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.
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