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Chapter 12
Error-Handling Techniques
In This Chapter
▶ Understanding the difference between programming errors and run-time errors
▶ Trapping and handling run-time errors
▶ Using the VBA on Error and Resume statements
▶ Finding out how you can use an error to your advantage
To err is human. To anticipate errors is divine. When working with VBA,
you should be aware of two broad classes of errors: programming errors
and run-time errors. (I cover programming errors, also known as bugs, in
Chapter 13.) A well-written program handles errors the way Fred Astaire
danced: gracefully. Fortunately, VBA includes several tools to help you identify
errors — and then handle them gracefully.
Types of Errors
If you’ve tried any of the examples in this book, you have probably encountered
one or more error messages. Some of these errors result from bad VBA
code. For example, you may spell a keyword incorrectly or type a statement
with the wrong syntax. If you make such an error, you won’t even be able to
execute the procedure until you correct it.
This chapter does not deal with those types of errors. Instead, I discuss runtime
errors — the errors that occur while Excel executes your VBA code.
More specifically, this chapter covers the following fascinating topics:
✓ Identifying errors
✓ Doing something about the errors that occur
✓ Recovering from errors
✓ Creating intentional errors (Yes, sometimes an error can be a good thing.)