On Error 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. We excel vba try catch will concern ourselves here only with run time errors. Typical run time errors include attempting to vba error handling best practices 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 error (Error excel vba on error exit sub 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 vba error handling in loop 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 be acceptable, even
On Error Goto Line
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
execution at a specified line upon hitting an error. Situation: Both programs calculate the square root of numbers. Square Root 1 Add the following code lines to the 'Square
Vba On Error Goto 0
Root 1' command button. 1. First, we declare two Range objects. We call vba iferror the Range objects rng and cell. Dim rng As Range, cell As Range 2. We initialize the Range object rng vba on error msgbox with the selected range. Set rng = Selection 3. We want to calculate the square root of each cell in a randomly selected range (this range can be of any size). In Excel VBA, http://www.cpearson.com/excel/errorhandling.htm you can use the For Each Next loop for this. Add the following code lines: For Each cell In rng Next cell Note: rng and cell are randomly chosen here, you can use any names. Remember to refer to these names in the rest of your code. 4. Add the following code line to the loop. On Error Resume Next 5. Next, we calculate the square root of http://www.excel-easy.com/vba/examples/error-handling.html a value. In Excel VBA, we can use the Sqr function for this. Add the following code line to the loop. cell.Value = Sqr(cell.Value) 6. Exit the Visual Basic Editor and test the program. Result: Conclusion: Excel VBA has ignored cells containing invalid values such as negative numbers and text. Without using the 'On Error Resume Next' statement you would get two errors. Be careful to only use the 'On Error Resume Next' statement when you are sure ignoring errors is OK. Square Root 2 Add the following code lines to the 'Square Root 2' command button. 1. The same program as Square Root 1 but replace 'On Error Resume Next' with: On Error GoTo InvalidValue: Note: InvalidValue is randomly chosen here, you can use any name. Remember to refer to this name in the rest of your code. 2. Outside the For Each Next loop, first add the following code line: Exit Sub Without this line, the rest of the code (error code) will be executed, even if there is no error! 3. Excel VBA continues execution at the line starting with 'InvalidValue:' upon hitting an error (don't forget the colon). Add the following code line: InvalidValue: 4. We
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 http://stackoverflow.com/questions/15811713/vba-nested-on-error-goto more about hiring 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 6.2 million programmers, just like you, http://www.techrepublic.com/blog/five-apps/five-tips-for-handling-errors-in-vba/ helping each other. Join them; it only takes a minute: Sign up VBA Nested On Error GoTo up vote 4 down vote favorite I have VBA code that is supposed to be nested error checking, but it does on error not. The code is psuedo as below. However, whenever an error occurs within an error (For instance, an error is tripped in the loop, goto SmallError occurs, and an error occurs in SmallError) The second GoTo is not used. The error then breaks the code. Ex: Error in Loop GoTo SmallError Error in SmallError Code Breaks (Here code should GoTo FatalError) Sub DoThings() On Error GoTo SmallError 'Coding Happens Do While(conditionhere) 'Looping things happen GoTo LoopResume vba on error SmallError: source = Err.source descript = Err.Description On Error GoTo Fatal Error 'Small error processing happens Resume LoopResume FatalError: source = Err.source descript = Err. Description On Error GoTo ExitError 'Fatal Error processing happens ExitError: Exit Sub LoopResume: count = count + 1 Loop On Error GoTo FatalError 'Finishing code happens End Sub excel vba error-handling nested goto share|improve this question asked Apr 4 '13 at 12:50 steventnorris 1,9701147104 add a comment| 2 Answers 2 active oldest votes up vote 4 down vote accepted You can't use an On Error statement within an error handler. See e.g. this article that explains this. What you CAN do however is to have a separate routine that handles the "regular error". This routine can have a "fatal error" handler. Your code would then look something like this: (Edit: Edited the code to enable exit when there is a fatal error): Sub DoThings() On Error GoTo SmallError Dim fatalExit As Boolean 'Coding Happens Do While(conditionhere) 'Looping things happen LoopResume: count = count + 1 Loop On Error Goto SmallError2 'Finishing code happens Exit Sub SmallError: handleError Err.Source, Err.Description, fatalExit If fatalExit Then Exit Sub Else Resume LoopResume End If SmallError2: handleError Err.Source, Err.Description, fatalExit Exit Sub End Sub Private Sub handleError(ByVal source As String,ByVal description As String, ByRef fatalExit As Boolean) On Error Goto FatalError 'Do "small error" handling here Exit
United States Australia United Kingdom Japan Newsletters Forums Resource Library Tech Pro Free Trial Membership Membership My Profile People Subscriptions My stuff Preferences Send a message Log Out TechRepublic Search GO Topics: CXO Cloud Big Data Security Innovation Software Data Centers Networking Startups Tech & Work All Topics Sections: Photos Videos All Writers Newsletters Forums Resource Library Tech Pro Free Trial Editions: US United States Australia United Kingdom Japan Membership Membership My Profile People Subscriptions My stuff Preferences Send a message Log Out Software Five tips for handling errors in VBA Effective error handling can mean the difference between a seamless, user-friendly experience and a problem-plagued application. These best practices will help ensure your apps run as intended, without a hitch. By Susan Harkins | in Five Apps, October 9, 2010, 1:15 AM PST RSS Comments Facebook Linkedin Twitter More Email Print Reddit Delicious Digg Pinterest Stumbleupon Google Plus A professional application always includes adequate error-handling routines to trap unexpected errors. Sometimes, the right handling means the user never knows the error occurred. At the very least, error-handling routines should address the problem, share adequate information on what the user should do next, and exit the program (if absolutely necessary) gracefully. You put a lot of effort into writing the procedures that run your custom applications. Why let a runtime error ruin it all? By employing a few best practices, you can improve error handling. 1: Verify and configure error settings Before you do anything, check the error-trapping settings. VBA, via the Visual Basic Editor (VBE), is flexible and allows you to determine how it responds to errors. To access these settings (shown in Figure A), in the VBE, choose Options from the Tools menu, and click the General tab: Break On All Errors: Stops on every error, even errors following a Resume Next statement. Break On Unhandled Errors: Stops for unhandled errors, but stops on the line calling the class (in class modules) rather than the line with the error, which can be problematic during debugging. Break In Class Modules: Stops at the actual error (line of code), but doesn't work as expected with Err.Raise, which generates an error of its own. Figure A Choose the most appropriate error-handling setting. Well-informed users can change this setting, so I recommend that you include a procedure, similar to the one in Listing A, to your application's startup routine. Listing A Function SetErrorTrappin