Bug Proofing Visual Basic: A Guide to Error Handling and Prevention
(Publisher: John Wiley & Sons, Inc.)
Author(s): Rod Stephens
ISBN: 0471323519
Publication Date: 11/01/98

INTRODUCTION

Part One—Work Environment

CHAPTER 1—Programming Philosophy

Manage Properly

Fight Bugs Every Step of the Way

Catch Bugs Early

Stay in Control

Intercept Unnecessary Work

Set Priorities

Change Priorities

Defer Optimization

Don’t Optimize

Get It Working First

Be Steady and Thorough

Code Offensively

Write for Others

Write for Humans

Code for the Ages

Code without Ego

Self-Test

Summary

CHAPTER 2—Work Habits

Keep a Notebook

Keep a Bug Log

Analyze the Bug Log

Save Everything

Do It Now

Fix It Now

Test It Now

If It Works, Don’t Fix It

Don’t Fiddle

Design Before You Code

Code When You Are Alert

Code in Manageable Pieces

Close Your Door

Self-Test

Summary

Part Two—Coding Style

CHAPTER 3—Variables

Explicitly Declare Variables

Use Option Explicit

Don’t Use Deftype Statements

Use Hungarian Notation

Hungarian Specifics

Purpose

A Word of Caution

Use Meaningful Names

Capitalize Consistently

Avoid Name Conflicts

Limit Scope

Use Static Variables

Use Specific Data Types

Use TypeOf and TypeName

Avoid Variants

Use Variant Subtype Functions

Beware the One Form

Self-Test

Summary

CHAPTER 4—Constants and Enums

Use No Magic Numbers

Dimension Arrays with Constants

Use NUM and MAX Constants

Use LBound and UBound

Give Related Values Related Names

Add and Remove Values with Care

Define Enumerated Values

Group Related Values

Self-Test

Summary

CHAPTER 5—Exposing Bugs

Verify Arguments

Use Debug.Assert

Use Stop

Validate Optional Parameters

Use Default Values

Avoid Optional Parameters

Name Optional Parameters

Validate ParamArray Parameters

Stop or Raise Errors When Appropriate

Use Tight Restrictions

Use LBound and UBound

Validate Data Structures

Validate at Startup

Validate at Shutdown

Validate While Running

Validate Forms and Classes

Clear Unused Variables

Use Else Statements

Verify Results

Self-Test

Summary

CHAPTER 6—Being Obvious

Don’t Use Clever Tricks

Document Tricks

Don’t Write Routines with Side Effects

Mix Data Types Cautiously

Use & and + Correctly

Mix Booleans and Integers Cautiously

Parenthesize Complex Expressions

Use Left$

Open and Close Files in the Same Routine

Put Separate Commands on Separate Lines

Specify Lower Bounds for Arrays

Don’t Use Static Routines

Use Private and Public

Use ByVal and ByRef

Use Line Continuation

Use Explicit Properties

Eliminate Random Behavior

Perform Short Actions First

Avoid Wizards

Use Meaningful Names

Standardize Abbreviations

Use Similar Names for Similar Purposes

Don’t Reuse Variables

Use Next i

Self-Test

Summary

CHAPTER 7—Comments

Comment Files

Identifying Information

Description

Entry Points

Dependencies

Known Issues

Method

Declarations

Example File Header

Comment Routines

Comment Event Handlers

Give Context, Not Content

Comment Portability Issues

Comment Plainly

Don’t Comment Continued Statements

Don’t Remove Comments

Format Comments Nicely

Use Lots of Comments

Self-Test

Summary

CHAPTER 8—Gotchas

Watch Precision in Tests

Control Float Loops with While

Control Float Loops with Integers

Control Date Loops

Don’t Resize Inside Loops

Watch for Circular References

Understand Form Lifetime

Initialize All Values

Use All Values

Return a Value

Beware Foreign Syntax

Never Use GoTo, Except...

Use GoTo for Error Handling

Use GoTo to Simplify

Exit in One Place

Exit before Error Handlers

Don’t Use IIF

Watch for Overflow and Underflow

Watch for Divide by 0

Be Aware of Argument Promotion

Avoid Error Codes

Don’t Assume Variable Sizes

Don’t Assume Constant Values

Self-Test

Summary

Part Three—Development

CHAPTER 9—Design

Design for Uniformity, Simplicity, Elegance

Avoid Creeping Featuritis

Start with Minimal Functionality

Avoid “Not Invented Here” Syndrome

Avoid the Bleeding Edge

Avoid Third-Party Products

Optimize Design, Not Code

Defer Optimization

Indent Consistently

Remove or Assert Assumptions

Catch Invalid Situations

Raise Errors for Exceptions

Use Enums for Status Codes

Return the Worst Data Possible for Errors

Don’t Use One Input for Multiple Purposes

Don’t Use One Output for Multiple Purposes

Keep Separate Tasks Separate

Examine Decisions Closely

Use FreeFile

Use ByVal

Separate Debug and Nondebug Code

Self-Test

Summary

CHAPTER 10—Encapsulation

Hide Internals

Encapsulate with Classes

Count Object Creation and Destruction

Initialize Objects

Use Property Procedures

Use Implements

Encapsulate with Types

Encapsulate with Controls

Encapsulate with Modules

Encapsulate with Subroutines

Encapsulate Errors

Encapsulate with Variables

Save Property Values

Use With

Don’t Use Nested Withs

Don’t Repeat Code

Encapsulate Library Calls

Self-Test

Summary

CHAPTER 11—Optimization

Optimize Algorithms

Defer Optimization

Profile First

Comment Optimizations

Use Slow Debugging Code

Understand Visual Basic’s Optimizations

Assume No Aliasing

Remove Array Bounds Checks

Remove Integer Overflow Checks

Remove Floating-Point Error Checks

Allow Unrounded Floating-Point Operations

Remove Safe Pentium FDIV Checks

Self-Test

Summary

Part Four—Error Handling

CHAPTER 12—Error Handling Fundamentals

Use On Error

On Error GoTo 0

On Error Resume Next

On Error GoTo Line

Leave Error Handlers

Resume

Resume Next

Exit Sub/Function/Property

End Sub/Function/Property

Err.Raise

Define Error Constants

Keep Error Handlers Separate

Understand Error Handler Scope

Don’t Nest Error Handlers

Write Bugproof Error Handlers

Always Be Prepared

Clean Up

Handle Errors in Objects

Handle Other Object Errors

Break on Errors

Self-Test

Summary

CHAPTER 13—Standard Error Handlers

Use a Systematic Approach

Catch Error Events

Present Error Messages

Unwind the Stack

Save Errors in a File

Save Errors in a Database

Send Email

Self-Test

Summary

Part Five—Post-Coding Activities

CHAPTER 14—Testing

Use Many Tests

Testing Techniques

Test Scope

Development Phase

Step through the Code

Hold Code Reviews

Test Exhaustively

Perform Black Box Testing

Perform White Box Testing

Consider Global Variables

Plan Tests

Test Continuously

Have the Proper Attitude

Write Test Routines

Look for Bugs

Test When You Are Alert

Test It Anyway

Test Ported Code

Start from the Immediate Window

Examine Variables

Modify Variables

Use Ctrl-F9

Examine Decision Statements

Anticipate Outputs

Fake Errors

Find Your Own Bugs

Have Someone Else Test Your Code

Don’t Shoot the Messenger

Fix Your Own Code

Simulate User Actions

Check Code Coverage

Keep Testing

Estimate the Number of Bugs

Estimate Bug Finding Time

Test User Interfaces from the Top Down

Test Code from the Bottom Up

Perform a Postmortem

Self-Test

Summary

CHAPTER 15—Profiling

Installing VB Code Profiler

How VBCP Works

Using VBCP

Analyzing Results

Line Timing

Function Timing

Line Hit Counting

Function Hit Counting

Self-Test

Summary

CHAPTER 16—Debugging Habits

Think First

Debug When You Are Alert

Code Properly While Debugging

Fix Your Own Bugs

Fix It Now

Come Back Later

Comment Repairs

See What Changed

Don’t Believe in Magic

Fix Routines, Not Lines

Fix Bugs, Not Symptoms

Look for Multiple Bugs

Do Not Experiment

Test Fixes

Simplify

Examine Decisions Closely

Look for Bugs Where There Are Bugs

Self-Test

Summary