Ms Word Vba Error Handling
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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
Vba On Error Goto
occur when VBA cannot correctly execute a program statement. We will concern ourselves here vba error handling best practices only with run time errors. Typical run time errors include attempting to access a non-existent worksheet or workbook, or attempting to divide by
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zero. The example code 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 excel vba try catch 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 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 vba error handling in loop 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 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 On Error Goto 0
Proper VBA error handling Excel, MS Office, Outlook, PowerPoint, Word Proper VBA error handling (3 votes, average: 4.67 out of 5) Loading... October 22, 2015 AnalystCave Leave a comment http://www.cpearson.com/excel/errorhandling.htm Writing VBA code is hard, but properly debugging code is even harder. Sounds like non-sense? Well I dare say developers spend more time debugging code than writing it. Looking for errors is what developers do most of the time! A critical part of debugging is proper error handling (VBA error handling in our case). Debugging is twice as hard as http://analystcave.com/vba-proper-vba-error-handling/ writing the code in the first place. Therefore, if you write the code as cleverly as possible, you are, by definition, not smart enough to debug it. โ Brian W. Kernighan However, today I don't want to expand on debugging VBA. That I covered in this post. No - today let's learn how to properly handle errors The Mouse Trap Analogy What is error handling? Take this analogy: Say you have a mouse (an error) in the house which turns up every now and then in the least expected moment as slips from your hands (an uncaught exception if you prefer). Without knowing where the mouse is and when it (the exception/error) will appear (in which line of code) you would need to search entire house to catch it (run through the entire code in our case). Obviously a better approach is setting mouse traps in several critical places in the house (corridors etc.) and waiting for the mouse to fall into your trap. So what is our mouse trap when speaking about VBA error h
the wrong time. The application may crash. A calculation may produce unexpected results, etc. You can predict some of these effects and take appropriate actions. Some other problems are not under your control. Fortunately, both Microsoft http://www.functionx.com/vbaexcel/Lesson26.htm Excel and the VBA language provide various tools or means of dealing with errors. Practical http://stackoverflow.com/questions/1038006/good-patterns-for-vba-error-handling Learning:Introducing Error Handling Open the Georgetown Dry Cleaning Services1 spreadsheet and click the Employees tab Click the Payroll tab Click the TimeSheet tab To save the workbook and prepare it for code, press F12 Specify the folder as (My) Documents In the Save As Type combo box, select Excel Macro-Enabled Workbook Click Save Introduction to Handling Errors To deal vba error with errors in your code, the Visual Basic language provides various techniques. One way you can do this is to prepare your code for errors. When an error occurs, you would present a message to the user to make him/her aware of the issue (the error). To prepare a message, you create a section of code in the procedure where the error would occur. To start that section, you create a label. Here is an example: vba error handling Private Sub cmdCalculate_Click() ThereWasBadCalculation: End Sub After (under) the label, you can specify your message. Most of the time, you formulate the message using a message box. Here is an example: Private Sub cmdCalculate_Click() ThereWasBadCalculation: MsgBox "There was a problem when performing the calculation" End Sub If you simply create a label and its message like this, its section would always execute: Private Sub cmdCalculate_Click() Dim HourlySalary As Double, WeeklyTime As Double Dim WeeklySalary As Double ' One of these two lines could produce an error, such as ' if the user types an invalid number HourlySalary = CDbl(txtHourlySalary) WeeklyTime = CDbl(txtWeeklyTime) ' If there was an error, the flow would jump to the label WeeklySalary = HourlySalary * WeeklyTime txtWeeklySalary = FormatNumber(WeeklySalary) ThereWasBadCalculation: MsgBox "There was a problem when performing the calculation" End Sub To avoid this, you should find a way to interrupt the flow of the program before the label section. One way you can do this is to add a line marked Exit Sub before the label. This would be done as follows: Private Sub cmdCalculate_Click() Dim HourlySalary As Double, WeeklyTime As Double Dim WeeklySalary As Double ' One of these two lines could produce an error, such as ' if the user types an invalid number HourlySalary = CDbl(txtHourlySalary) WeeklyTime = CDbl(txtWeeklyTime) ' If there was an error, the
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 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, helping each other. Join them; it only takes a minute: Sign up Good Patterns For VBA Error Handling up vote 47 down vote favorite 30 What are some good patterns for error handling in VBA? In particular, what should I do in this situation: ... some code ... ... some code where an error might occur ... ... some code ... ... some other code where a different error might occur ... ... some other code ... ... some code that must always be run (like a finally block) ... I want to handle both errors, and resume execution after the code where the error may occur. Also, the finally code at the end must ALWAYS run - no matter what exceptions are thrown earlier. How can I achieve this outcome? exception vba exception-handling share|improve this question edited Apr 15 '13 at 8:22 Atif Aziz 23k145165 asked Jun 24 '09 at 12:17 jwoolard 2,51062534 add a comment| 9 Answers 9 active oldest votes up vote 69 down vote accepted Error Handling in VBA On Error Goto ErrorHandlerLabel Resume (Next | ErrorHandlerLabel) On Error Goto 0 (disables current error handler) Err object The Err object's properties are normally reset to zero or a zero-length string in the error handling routine, but it can also be done explicitly with Err.Clear. Errors in the error handling routine are terminating. The range 513-65535 is available for user errors. For custom class errors, you add vbObjectError to the error number. For not implemented interface members in a derived class, you should use the constant E_NOTIMPL = &H80004001. Option Explicit Sub HandleError() Dim a As Integer On Error GoTo errMyErrorHandler a = 7 / 0 On Error GoTo 0 Debug.Print "This line won't be executed." DoCleanUp: a = 0 Exit Sub errMyErrorHandler: MsgBox Err.Description, _ vbExclamation + vbOKCancel, _ "Error: " & CStr(Err.Number) Resume DoCleanUp End Sub Sub RaiseAndHandleError() On Error GoTo errMyErrorHandler ' Th