Break mode is a temporary suspension of program execution in the development environment. In Break mode, you can examine, debug, reset, step through, or continue program execution.
When you select Allow Break on Errors, unhandled errors found during the execution of a VBA macro suspend the execution of the macro and display the Visual Basic Editor at the point of the error in the macro. Enter a number when prompted for the numerator, and enter 0 when prompted for the denominator. You should see an error message in a message box. Click the Play button to run the routine again. Enter a letter when prompted for the numerator.
You should see a different error message. If you enter two numbers when prompted, the program runs as intended and provides an answer. We have detected that you are using an Ad Blocker and kindly ask you to consider placing Cadalyst. Ads help support our ability to provide you all our articles and papers at no cost to you. Thank you for your consideration and support. Number Case 11 MsgBox "You tried to divide by zero. Description End Select End Sub 6. About the Author: Andrew G.
You can also check the validity of the data relative to the application. Suppose you needed a whole number between one and Your input validation function could check the data input to make sure it conforms to the desired range or post a message to the user if it is out of range.
The value can then be reset to the maximum or minimum acceptable. In both cases you can create a text message dialog box on the fly to tell users about the problem with their input. The strings provided can be quite long and may include carriage-control characters.
Most error potentials can be caught at the input stage; however, there are many more problems that could be waiting for your program to wander into. Suppose the data all looks good individually, but is poorly conditioned for the calculations to be performed with it. This can happen in more advanced applications involving many equations or repeated applications of equations to arrive at a solution.
Ill-conditioned data can cause errors such as division by zero or an attempt to get a square root of a negative number. In many cases you should be able to detect bad data during the input phase. However, you may want to add additional tests in your code to make sure everything is proceeding okay when there is even the slightest probability of a problem. The error object can be activated in your code for a function or subroutine. It is only active inside the subroutine in which you turn it on.
Should that subroutine call another function or subroutine, the error object is suspended until the invoked function has completed. If you want to provide error handling in the called function, you will need to enable the error object within it as well. You can force execution to continue, force the program to jump to another place in the code, or cause another function to be run. This may be a desirable thing if your function is reading a data file.
If the end of file is encountered or a bad record is returned, your program can react by just testing the error object value to see if there was a problem. Thus a test to see if ERR. The error object also contains a property with the description text that can be used in messages or for your own knowledge when devising a scheme to handle the anticipated errors in the data that may trigger unwanted problems.
However, it does contain more error-catching capabilities that can be used in your programming since the error-handling system can be set up to span any scope of functions you need. The first is a global symbol that can be defined as a function. The value is a string describing the error that has caused the error handler to trigger.
This string is the same error string you will see at the command line if the error function has not been activated. The error symbol spans all the functions in your application. Should any error occur that Visual LISP deems as fatal in nature, the error function will be activated.
0コメント