Debugging Visual Basic programs  

ENGR 2200 - Numerical Methods in Engineering I (Fall 2001) and Graduate-Level VB/VBA Course (Spring 2002)

Gilberto E. Urroz - ph. 435-797-3379 - gurro@cc.usu.edu - EC 214 - fax 435-797-1185

Appendix D in the Visual Basic textbook (Schneider) (pp. 719-728) provides information on the use of the Visual Basic Debugging Tools.  Examples for debugging are available for download in the Visual Basic exercise page.  

Debugging instructions also included in Chapter 6 of Gottfried's book.

Some commands/concepts for debugging

• Select option Step Into in menu Debug to start the debugger

• [ F8 ] = Step into: let's you move step-by-step through a program.

• Arrow and yellow highlight indicate which command is waiting execution.

• [Shift][ F8 ] = Step over: continues normal program execution.

• Place cursor over a variable to see current value of that variable.

• The immediate window (shows up at the bottom of the code window when debugging) lets you perform Basic commands without interfering with the VB program.

• The Add Watch option in the Debug menu lets you define variable names to watch as the program is debugged. 

• The Edit Watch option in the Debug menu lets you modify or delete variable names under watch.

• Breakpoints are points where debugging will be triggered within your program. 

• To set a breakpoint click on the left margin of the code window at the level of the command line that you want to set as the breakpoint.  A red circle will show up in the left margin of the window and the command will be highlighted in red.

• To remove a breakpoint click on the breakpoint line.  The red circle and highlight will disappear.