Error Handling Visual Basic Excel
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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 excel macro error handling user entering a negative value where only a positive number is excel vba error handling best practice acceptable; and run time errors, that occur when VBA cannot correctly execute a program statement. We will concern excel vba error handling in loop ourselves here only with run time errors. Typical run time errors include attempting to access a non-existent worksheet or workbook, or attempting to divide by zero. The example excel vba error handling type mismatch 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 ensure that run time errors do not occur later. In Excel, this includes ensuring that required workbooks and worksheets are present and that required
Excel Vba Error Handling 1004
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 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, Ex
generally put more focus on the coding part and getting the desired result but during this process we forget an important thing i.e. Error handling. Error handling is an important part of every code and VBA On Error Statement is an easy way for
Excel Vba Error Handling Find Method
handling unexpected exceptions in Excel Macros. A well written macro is one that includes proper exception excel vba error handling exit sub handling routines to catch and tackle every possible error. Error handling is important because in case of any unexpected exceptions your code doesn’t break. Even excel vba error handling not working if any fatal unexpected error occurs in the code then also you should ensure that the code should terminate gracefully. Definition of VBA On Error Statement: On Error statement instructs VBA Compiler, what to do in case any runtime exception are thrown. http://www.cpearson.com/excel/errorhandling.htm Syntax of On Error Statement: Basically there are three types of On Error statement: 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 Root 1' command button. http://www.excel-easy.com/vba/examples/error-handling.html 1. First, we declare two Range objects. We call the Range 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 (this range can be of any size). In Excel VBA, you can use the For Each Next loop for error handling 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 a value. In Excel VBA, we can use the Sqr function for this. Add excel vba error 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 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 roo