Certain other actions reset the Err object and remove the previous error information. The program should check Err.Number immediately after the statement in question. If the value Err.Number is nonzero, the operation caused an error and the program can take special action. When a program uses On Error Resume Next, it should check the Err object after every operation that might cause an error. When it encounters an error, the program continues execution after the statement that caused the error. On Error Resume Next makes the program ignore errors. If the program encounters an error after this statement executes, it crashes.
It simply cancels any currently installed error handler assigned by a previous On Error GoTo line or On Error Resume Next. On Error GoTo 0 is relatively straightforward. The three forms are described in the following sections. These forms tell Visual Basic what it should do when the program encounters an error. This statement can take one of three forms: After reading this chapter you will be able to write basic error handlers to protect your programs from the unexpected.Ī Visual Basic program uses the On Error statement to register error handling code. It tells how a program installs and removes error handlers, and it explains some of the idiosyncrasies of error handling code. This chapter explains the family of On Error statements Visual Basic uses to handle errors. When they do occur, and how to recover from unexpected errors.
This book also explains how to reduce theĬhances of errors occurring in a program, how to detect errors There is a lot more to writing bug proof programs than just This chapter explains theįundamentals of using error handlers in Visual Basic. This article contains roughly half of Chapter 12 of the bookīug Proofing Visual Basic. Tutorial: Bug Proofing - Error Handling Fundamentals VB Helper Tutorial: Bug Proofing - Error Handling Fundamentals
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