On Error Not Working In Vba
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Vba Error Handling In Do While Loop
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 Excel reset error handler vba VBA: On Error Goto statement not working inside For-Loop up vote 7 down vote favorite 1 I'm trying to cycle through a table in excel. The first three columns of this table have text headings, the rest of them have dates as excel vba error handling best practice headings. I want to assign those dates, sequentially, to a Date-type variable, and then perform some operations based on the date To do this I am using a foreach loop on myTable.ListColumns. Since the first three columns do not have date headers, I have tried to set the loop up so that, if there is an error assigning the header string to the date-type variable, the loop goes straight to the next column This seems to work for the first column. However, when the second
Vba On Error Goto
column's header is 'assigned' to the date-type variable, the macro encounters an error even though it is within an error-handling block Dim myCol As ListColumn For Each myCol In myTable.ListColumns On Error GoTo NextCol Dim myDate As Date myDate = CDate(myCol.Name) On Error GoTo 0 'MORE CODE HERE NextCol: On Error GoTo 0 Next myCol To reiterate, the error is thrown on the second round of the loop, at the statement myDate = CDate(myCol.Name) Can anyone explain why the On Error statement stops working? excel vba excel-vba for-loop error-handling share|improve this question asked Aug 17 '12 at 1:52 Swiftslide 41751828 Rather than using an error as your control structure, maybe an IF with an IsDate function would be more suitable in this scenario? –ray Aug 17 '12 at 2:29 1 If you are "blindly" handling the error - rather than taking specific action on an error type - then you should just use an On Error Resume Next outside your loop. At the moment you are using error handling afresh on each column. –brettdj Aug 17 '12 at 2:40 1 @brettdj, I don't think you can just resume next. The whole idea is to skip over the "more code here" code if the date conversion fails. So you need to go into a handler so that you can resume to a specific line. In addition, you only want the handler enabled for the date conversion, not the entire loop body. –paxdiablo Aug 17 '12 at 3:01
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 on error goto line is acceptable; and run time errors, that occur when VBA cannot correctly execute try catch vba a program statement. We will concern ourselves here only with run time errors. Typical run time errors include attempting to
Vba On Error Goto 0
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 11) when we want to deliberately raise an http://stackoverflow.com/questions/11998836/excel-vba-on-error-goto-statement-not-working-inside-for-loop 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 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 http://www.cpearson.com/excel/errorhandling.htm 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 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 t
frequent questions I come across relates to the situation where an active and enabled error handler section handles the first error as expected but then fails to handle any subsequent errors. (An enabled error handler is one that is turned on by an On Error statement and an active http://excelmatters.com/2015/03/17/on-error-wtf/ error handler is an enabled handler that is in the process of handling an error.) Here's the explanation (it's a little long, but bear with me!): The On Error statement is the heart of VBA error-handling. Without an On Error statement, any run-time error that occurs will display an error message, and code execution will stop. There are 4 distinct On Error options: On Error Resume Next On Error GoTo some_label/line_number On Error Goto 0 On Error Goto -1 On Error Resume Next This is on error the simplest error handling option but also the most dangerous and most often misused. It ensures that when a run-time error occurs, control simply goes to the statement immediately following the statement where the error occurred, and execution continues from that point. There is no message to alert the user as to the fact that an error has occurred, or to what it might be. A typical good use of this structure is when there is a predictable error that you want to override – vba error handling often assigning an object that may or may not exist to a variable. For example, when testing for the existence of a worksheet in a workbook, you can loop through all the worksheets checking the name of each one, or you can employ an On Error Resume Next statement like this: Dim ws as Worksheet On Error Resume Next Set ws = activeworkbook.worksheets("some name") If not ws is nothing then ' do stuff End If The danger of this is if you do not remember to reset error handling (by either simply disabling it with On Error Goto 0 or enabling an error handler – see below) all further errors in your code will be suppressed, which can make problems very hard to locate and debug – you may not even notice them until your code is already in real use, which is never a good thing! I frequently see people simply put On Error Resume Next at the top of their procedures when they can't figure out why an error is occurring – THIS IS NOT A GOOD IDEA!! On Error GoTo some_label/line_number Enables the error-handling routine that starts at the specified line label or number. If a run-time error occurs, control passes to that specified line, making the error handler active. (The specified line must be in the same procedure as the On Error statement, or a compile-time error will occur). On Error GoTo 0 Disables any enabled error handler, including On Error Resume Next, in the current procedure. (It doesn't spe