Chapter 11 - Implementing Error-Handling Features in an Application

( Contents )

This chapter discusses error handling in Visual Basic applications. Being able to trap, identify, and handle errors is a vital part of developing a user-friendly application. Error trapping and error handling can provide important feedback to the user about why an error occurred. The information provided through error handling can also help the developer find, correct, and prevent errors.

Trapping and handling errors in an Executable is covered in this chapter as well as dealing with errors at design time while debugging a project.

You will learn different ways to trap errors when they occur and to handle different error situations. In this chapter, recommendations for creating common error handling procedures are provided along with examples of how error information should be presented to the user.

This chapter covers the following topics:

• Setting error handling options
• The Err object
• Handling errors in code
• The error handling hierarchy
• Common error handling routines
• The Error function
• The Error statement

Contents

1. Setting Error-Handling Options
      Setting Break on All Errors
      Setting Break in Class Modules
      Setting Break on Unhandled Errors

2. Using the Err Object
      Properties of the Err Object
         Number Property
         Description Property
         Source Property
         HelpFile Property
         HelpContext Property
         LastDLLError Property
      Methods of the Err Object
      Using the vbObjectError Constant

3. Handling Errors in Code
      Using the On Error Statement
      Inline Error Handling
      Error-Handling Routines
      Trappable Errors

4. Using the Error-Handling Hierarchy

5. Common Error-Handling Routines

6. Using the Error Function

7. Using the Error Statement

8. Inline Error Handling