Access Vba Error Trapping
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Access Vba Error Handling
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Ms Access Vba Error Handling Example
Submit to the Office Store All Documentation https://www.yammer.com/ http://feeds.feedburner.com/office/fmNx How do I... Miscellaneous Maintenance Maintenance Handle Run-Time Errors in VBA Handle Run-Time Errors in VBA Handle Run-Time vba excel on error resume next Errors in VBA Compact and Repair a Database Recover Tables Deleted from a Database Handle Run-Time Errors in VBA TOC Collapse the table of content Expand the table of content This documentation is archived and is not being maintained. This documentation is archived and is not being maintained. Handle Run-Time Errors in VBA on error exit sub vba Office 2013 and later Other Versions Office 2010 Contribute to this content Use GitHub to suggest and submit changes. See our guidelines for contributing to VBA documentation. Errors and Error Handling When you are programming an application, you need to consider what happens when an error occurs. An error can occur in your application for one of two of reasons. First, some condition at the time the application is running makes otherwise valid code fail. For example, if your code attempts to open a table that the user has deleted, an error occurs. Second, your code may contain improper logic that prevents it from doing what you intended. For example, an error occurs if your code attempts to divide a value by zero. If you have not implemented error handling, Visual Basic halts execution and displays an error message when an error occurs in your code. The user of your application is likely to be confused
a full version of Access, while a run-time version just crashes. For a more detailed approach to error handling,
Vba Error Handling Examples
see FMS' article on Error Handling and Debugging. The simplest approach ms access error handling best practice is to display the Access error message and quit the procedure. Each procedure, then, will have this
Vba Error Handling Best Practices
format (without the line numbers): 1 Sub|Function SomeName() 2 On Error GoTo Err_SomeName ' Initialize error handling. 3 ' Code to do something here. 4 Exit_SomeName: ' Label https://msdn.microsoft.com/en-us/library/office/ff193267.aspx to resume after error. 5 Exit Sub|Function ' Exit before error handler. 6 Err_SomeName: ' Label to jump to on error. 7 MsgBox Err.Number & Err.Description ' Place error handling here. 8 Resume Exit_SomeName ' Pick up again and quit. 9 End Sub|Function For a task where several things could go wrong, lines 7~8 will be replaced http://allenbrowne.com/ser-23a.html with more detail: Select Case Err.Number Case 9999 ' Whatever number you anticipate. Resume Next ' Use this to just ignore the line. Case 999 Resume Exit_SomeName ' Use this to give up on the proc. Case Else ' Any unexpected error. Call LogError(Err.Number, Err.Description, "SomeName()") Resume Exit_SomeName End Select The Case Else in this example calls a custom function to write the error details to a table. This allows you to review the details after the error has been cleared. The table might be named "tLogError" and consist of: Field Name Data Type Description ErrorLogID AutoNumber Primary Key. ErrNumber Number Long Integer. The Access-generated error number. ErrDescription Text Size=255. The Access-generated error message. ErrDate Date/Time System Date and Time of error. Default: =Now() CallingProc Text Name of procedure that called LogError() UserName Text Name of User. ShowUser Yes/No Whether error data was displayed in MsgBox Parameters Text 255. Optional. Any parameters you wish to record. Below is a procedure for writing to this table. It optionally a
Comments Before delving into actual programming functions and sub-routine, we must first establish an error handler. An error handler is a bit of code which will do pre-defined actions http://www.devhut.net/2010/10/07/ms-access-vba-error-handling/ whenever an error occurs. For instance, generate a message to the user or developper http://www.databasedev.co.uk/error-handling.html describing the nature of the error. For an error handler to be useful, it must provide a minimum of information in its message to the user. Below is a typical example of an error handler I use. Modify it in any way to suit your exact needs. On Error GoTo Error_Handler 'Your code will go vba error here Error_Handler_Exit: On Error Resume Next Exit {PROCEDURE_TYPE} Error_Handler: MsgBox "The following error has occured" & vbCrLf & vbCrLf & _ "Error Number: " & Err.Number & vbCrLf & _ "Error Source: {PROCEDURE_NAME}/{MODULE_NAME}" & vbCrLf & _ "Error Description: " & Err.Description, vbCritical, _ "An Error has Occured!" Resume Error_Handler_Exit A Concrete Example Sub HelloWorld() On Error GoTo Error_Handler MsgBox "Hello Word!" Error_Handler_Exit: On Error Resume vba error handling Next Exit Sub Error_Handler: MsgBox "The following error has occured" & vbCrLf & vbCrLf & _ "Error Number: " & Err.Number & vbCrLf & _ "Error Source: YourModuleName/HelloWorld" & vbCrLf & _ "Error Description: " & Err.Description, vbCritical, _ "An Error has Occured!" Resume Error_Handler_Exit End Sub Note: Although VBA provides programmers with the possibility of using the err.source statement, it sadly does not help truly identify the culprit of the current error. This is why you must manually enter in the {MODULE_NAME} / {PROCEDURE_NAME} for each error handler. Trust me, although it may take a few extra seconds to do, it will same you loads of troubleshooting time later on (I'm talking from experience)!!! Also, if you are going to be doing some serious vba (MS Access, Word, Excel, …) work and not just a little tinkering, you should most probably seriously consider looking into the Mz-Tools add-in (free with no strings attached) in conjunction with implementing Allen Browne Error Log (for database developers). These two tools/approaches will greatly simplify and standardize your work!!! View ratings Rate this article Rate this article Article ratingsCurrent average ratings. Ease of understanding 4.7 3 ratings Helpful/Useful 4.7 3 ratings Complete 4.0 3 ratings Easy to find
GUI Design GUI Design Examples Submit Your Examples Resources Resources Database News Knowledge Base Microsoft Access Products, Tools & Add-In's Online Shop UK Visitors US Visitors Info Contact Us Advertise With Us Link To Us Write For Us Competitions Microsoft Access VBA Error Handling In Microsoft Access Error handling routines are very powerful tools in Microsoft Access if they are used correctly. Surprisingly though, errors and their properties are relatively unknown to a large part of the development community. To effectively implement error handling in your applications, it is necessary to know the resources that are available when your program encounters an error. Assuming we are working with non-executable programs (.mdb's or .accdb's), the most important thing to understand is the global settings for error trapping in our VBA procedure. Under the "Tools » Options" menu, then on the "General" Tab there are three options for error trapping: Break on all errors » Stops code execution when an error is encountered. Break in class module » Stops code execution in class modules only. Break on unhandled errors » Stops code execution only if there is no error handling routine present in the procedure. This is the global setting for error handling. So, if error traps are present in our procedures, they will be ignored if we have specified the "Break on all errors" option. In the following image, we've done just that: There are three important statements in an error handling routine: On Error, Resume and GoTo. Typically, they will appear together at the beginning of a procedure: On Error Resume Next On Error GoTo 0 The "Resume" and "GoTo" statements simply tell VBA what to do when an error is encountered. First, Resume has two primary actions associated with it: Resume Next » Ignores the encountered error and continues execution with the next line of code. Resume (label) » After an error occurs, code execution resumes on the first line of code after the labeled line. Similarly, GoTo is usually found in two forms: GoTo 0 » Terminates the procedure's error handler. In other words, this statement disables it. GoTo (label) » Identical to the Resume statement. Execution jumps to the first line after the labeled line. So which is best to use? It all depends on what the error possibilities are. But there a few oth