Error Handling With 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 excel vba error handling cannot correctly execute a program statement. We will concern ourselves here only with run time
Vba Error Handling Best Practices
errors. Typical run time errors include attempting to access a non-existent worksheet or workbook, or attempting to divide by zero. The example code error handling vba access in this 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
Vb Error Handling
not occur later. In Excel, this includes ensuring that required workbooks and 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 vba message box 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 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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us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is vbscript error handling a community of 4.7 million programmers, just like you, helping each other. Join them; it only takes a minute: Sign up Properly Handling Errors in VBA (Excel) up vote 34 down vote favorite 19 http://www.cpearson.com/excel/errorhandling.htm I've been working with VBA for quite a while now, but I'm still not so sure about Error Handling. A good article is the one of CPearson.com However I'm still wondering if the way I used to do ErrorHandling was/is completely wrong: Block 1 On Error Goto ErrCatcher If UBound(.sortedDates) > 0 Then // Code Else ErrCatcher: // Code End If The if clause, because if it is true, it http://stackoverflow.com/questions/6028288/properly-handling-errors-in-vba-excel will be executed and if it fails the Goto will go into the Else-part, since the Ubound of an Array should never be zero or less, without an Error, this method worked quite well so far. If I understood it right it should be like this: Block 2 On Error Goto ErrCatcher If Ubound(.sortedDates) > 0 Then // Code End If Goto hereX ErrCatcher: //Code Resume / Resume Next / Resume hereX hereX: Or even like this: Block 3 On Error Goto ErrCatcher If Ubound(.sortedDates) > 0 Then // Code End If ErrCatcher: If Err.Number <> 0 then //Code End If The most common way I see is that one, that the Error "Catcher" is at the end of a sub and the Sub actually ends before with a "Exit Sub", but however isn't it a little confusing if the Sub is quite big if you jump vice versa to read through the code? Block 4 Source of the following Code: CPearson.com On Error Goto ErrHandler: N = 1 / 0 ' cause an error ' ' more code ' Exit Sub ErrHandler: ' error handling code' Resume Next End Sub Should it be like in Block 3 ? Thank you for reading my question Greetings skofgar exce
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 Root 1' command button. 1. First, we declare two Range objects. We call the Range http://www.excel-easy.com/vba/examples/error-handling.html objects rng and cell. Dim rng As Range, cell As Range 2. We initialize the Range object rng with the selected range. Set rng = Selection 3. We want to calculate the square root of each cell in a randomly selected range http://www.techrepublic.com/blog/five-apps/five-tips-for-handling-errors-in-vba/ (this range can be of any size). In Excel VBA, 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 error handling 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 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 vba error handling 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 keep our error code simple for now. We display a MsgBox with some text and the address of the cell where the error occurred. MsgBox "can't calculate square root at cell " & cell.Address 5. Add the following line to instruct Excel VBA to resume execution after executing the error code. Resume Next 6. Exit the Visual Basic Editor and test the program. Result: Do you like this free website? Please share this page on Google+ 3/6 Completed! Learn more about macro errors >Go to Top: Error Handling|Go to Next Chapter: String Manipulation Chapter<> Macro Er
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