Exploring Microsoft Access
Chapter 8
Creating More Powerful
Applications:
Objectives
(1 of 2)
• Describe relationship of VBA to Microsoft Office • Describe components of the Module window
• Describe two ways to create an event procedure • Explain how the Quick Info and Complete Word
features simplify entry of VBA statements
Objectives
(2 of 2)
• Describe MsgBox parameters
• Create an event procedure to facilitate data entry through keyboard shortcuts
• Create an event procedure that substitutes an application-specific message for the standard Access error messages
Overview
• VBA is a programming language to build
truly useful Access applications
• VBA is event driven: Procedures respond to
specific events
• VBA can modify procedures that Access
has already created
Introduction to VBA
• Data validation
• Facilitate data entry, including creating
keyboard shortcuts
• Error trapping
Modules and Procedures
• Visual Basic code is developed in units called
procedures
• Event procedures: run automatically in
response to an event
Modules
• All procedures are stored in modules; one module contains one or more procedures
• Every form in Access has its own module (Class module), which contains procedures for that form • Private procedure: accessible only from within the
module in which it is contained
• Public procedure: accessible from anywhere
Module Window
Name of procedure (Form_Close)
MsgBox statement
Name of next Procedure
MsgBox Statement
• MsgBox takes three arguments (known as
parameters)
• Prompt: Specifies the message text
• Buttons: Type of command buttons and icon
• Title: Text that appears in title bar of the
Create an Event Procedure
Select Event tab
Click On Current Select Code Builder Right click on
On Current Event Procedure
Procedure header
Name of Combo Box from step 3
Facilitating Data Entry
• Use the Default property to specify default
values for certain fields
• Use VBA to create keyboard shortcuts
KeyDown Event Procedure
Select Form in the Object list box
Select KeyDown
from the Procedure List box Key words
ShortCut Command Button
Select the command button Properties All tab
Change Name to ShortCutButton
Change Caption to &ShortCuts
Error Trapping
• Produce more user-friendly error message • Find the error number using the Immediate
window
• Use case statements to test the value of an
incoming variable and produce the appropriate statement
• Once error is detected, Call MsgBox statement to display your user-friendly error message
Error Event Procedure
Case 1 Error numbers
Case 2
Data Validation
• Invalid data corrupts validity of information
• Data validation is therefore crucial
• Use VBA to extend data validation
capabilities within Access
MsgBox Function vs. Statement
•
MsgBox function
: displays a prompt to
the user, then returns a value
- Requires parentheses around arguments
Chapter 8 Summary
(1 of 2)
• VBA is a subset of Visual Basic
• VBA is accessible by all Microsoft Office applications
• All VBA procedures are stored in modules
Chapter 8 Summary
(2 of 2)
• All procedures are either public or private:
Private—accessible only from within its module public—accessible from anywhere
• Event procedures were created to illustrate how VBA is used to improve an application
• MsgBox function has three arguments:
