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Part III: Programming Concepts
After you’ve debugged your code, be sure to remove all the Debug.Print
statements. Even big companies like Microsoft occasionally forget to remove
their Debug.Print statements. In several previous versions of Excel, every
time the Analysis ToolPak add-in was opened, you’d see several strange messages
in the Immediate window (as shown in Figure 13-4). That problem was
fixed in Excel 2007.
Figure 13-4:
Even professional
programmers
sometimes
forget to
remove their
Debug.Print
statements.
Using the VBA debugger
The Excel designers are intimately familiar with the concept of bugs. consequently,
Excel includes a set of debugging tools that can help you correct problems
in your VBA code. The VBA debugger is the topic of the next section.
About the Debugger
In this section, I discuss the gory details of using the Excel debugging tools.
These tools are much more powerful than the techniques I discuss in the previous
section. But along with power comes responsibility. Using the debugging
tools takes a bit of setup work.
Setting breakpoints in your code
Earlier in this chapter, I discuss using MsgBox functions in your code to monitor
the values of certain variables. Displaying a message box essentially halts
your code in mid-execution, and clicking the OK button resumes execution.
Wouldn’t it be nice if you could halt a routine’s execution, take a look at the
value of any of your variables, and then continue execution? Well, that’s
exactly what you can do by setting a breakpoint. You can set a breakpoint in
your VBA code in several ways: