1. Exploring Microsoft Access Chapter 8 Creating More Powerful Applications: Introduction to VBA

2. 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 Create a combo box to locate a record on a form

3. 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 Describe several types of data validation

4. 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 Provide an appreciation for what can be accomplished with VBA

5. Introduction to VBA Data validation Facilitate data entry, including creating keyboard shortcuts Error trapping Enhance communication with the user by using message boxes

6. Modules and Procedures Visual Basic code is developed in units called procedures Event procedures: run automatically in response to an event General procedures: called explicitly from within another procedure

7. 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: where procedures in a module are displayed and edited

8. Module Window Name of procedure (Form_Close) MsgBox statement Name of next Procedure (Form_Current) End of procedure

9. 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 message box

10. Create an Event Procedure Select Event tab Click On Current Select Code Builder Right click on Form Selector box and choose Properties

11. On Current Event Procedure Procedure header Name of Combo Box from step 3 Complete Word will provide completion options

12. Facilitating Data Entry Use the Default property to specify default values for certain fields Use VBA to create keyboard shortcuts A KeyDown event procedure can implement keyboard shortcuts

13. KeyDown Event Procedure Select Form in the Object list box Select KeyDown from the Procedure List box Key words Appear in blue

14. ShortCut Command Button Select the command button Properties All tab Change Name to ShortCutButton Change Caption to &ShortCuts Command Button tool

15. 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 Else will execute if all Case statements fail

16. Error Event Procedure Case 1 Error numbers Case 2 Else statement

17. Data Validation Invalid data corrupts validity of information Data validation is therefore crucial Use VBA to extend data validation capabilities within Access Use a nested IF statement to remind users to leave no fields empty

18. MsgBox Function vs. Statement MsgBox function: displays a prompt to the user, then returns a value - Requires parentheses around arguments MsgBox statement: simply displays a message, does not use parentheses

19. 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 Every form in Access has its own module that contains the event procedures for that form

20. 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: message, intrinsic constant, and title bar message