1. CSI 101 Elements of Computing – Spring 2009
Lecture #11 – Structures of Visual Basic
Wednesday, March 18th

2. Visual Basic Form
Primary means for user to interact with VB application
Contains Windows constructs to hold particular information
We will discuss those later
Most applications have more than one form
Particular events cause a new form to open

3. Parts of a Form Title Menu Bar Tool bar Status bar Contains words
Produces dropdown menus
Tool bar
Contains icons
Status bar
Bottom
Contains messages or other information

4. Example of Parts of a Form
Note you can have more than one tool bar. There is only one Title bar, menu bar, and status bar, however.

5. Types of Forms Splash page Main Menu (Switchboard) Data Entry
First screen to appear
Main Menu (Switchboard)
Provides paths to major functions
Most applications have screen menus as well as menu bars
Easy to follow logical path to get to particular function
Data Entry
Reporting/Data Display

6. Splash Page Example

7. Main Menu – Simple Example

8. Main Menu - Functional
This one takes the same philosophy as a menu bar, but has better labels

9. Submenu – Simple Example
Obtained by clicking on the Inventory button from the form on Slide 7

10. Search Specifications
Branch Manager Selector Tool
Search Specifications
Results
Which best describes selection requirements?
Enter some PNC Branch info
Find competitor branches near PNC branch
Cost Center:
Bank Number:
Find branches near specific competitor
Company #
Should headquarters be included in search results?
Address
No (default)
City
State
Zip
Yes
Select a PNC Branch
What about Denovo competitive branches?
Exclude (default)
Include
Only show Denovo
Enter some Competitive Branch Info
How many branches should be displayed in results?
Parent Bank Name
Drop list 20
Enter number between 1 and 50
Address
This is a sample of data interactive screen. There are option buttons, text boxes, and command buttons. Go over each.
City
State
Zip
How many miles radius should be searched?
Select a Competitor Branch 10
Enter number between 1 and 50
Search
Start Over

11. Data Entry Sample – Text Boxes

12. Search Specifications
Branch Manager Selector Tool
Search Specifications
Results
Cost Center / Bank:No
Address
PNC Branch
City
State
Zip
Deposit Growth
Deposits
Market Share 7% 3%
Deposit Growth
Deposits
Market Share
Denovo? HQ
Bank Name
Distance (mi)
Address
City
State
Zip
Change Search
Export All
Export Selected
Print All
Print Selected

13. Components of a Form Objects Events Code Hold and display information
Activities that trigger code procedures to run
Code
General declarations and Procedures

14. Types of Procedures Event Procedures Subroutines Functions
Run when a particular event occurs
“Attached” to a particular object
Subroutines
Available to any code procedure via CALL
Functions
Available to any code procedure

15. Form Events Several, but here are the common ones:
Load – occurs when Form is requested
Activate – occurs when Form is being displayed in preparation for starting
GotFocus – occurs when Form is displayed and ready for user interaction
LostFocus – occurs when user is done with Form
Deactivate – occurs when Form is closing
Unload – occurs when Form is being removed

16. Event Procedure Same structure as subroutines Name is object_event
Ex: Sub Form_Load()
Starts with Scope
Public or Private
Private by default
Means only available to form
Some subroutines and functions you write can be Public
Available to any form or procedure in entire application

17. Form Event Procedure Example
Private Sub Form_Load()
Dim boolFlag As Boolean
Dim intCount As Integer
Dim strFilter As String
If strFilter <> "" Then :
End If
End Sub

18. Form Objects Plenty, but the ones we’ll be working with: Text box
Label – Text
Command button
List box
Combo box – List box plus text box
Checkbox – True/False
Option button – Select one of a group

19. Object Elements Properties Events Event Code Attributes of object
Ex: Caption (“label” on command button)
Properties can have properties
Ex: Font in text box
Size, type, bold, etc
Events
Event Code

20. Object Properties Referenced with dot notation
Ex: CommandOK.Caption = “OK”
Ex: Text1.Font.Size = 16
Can be referenced or changed by any procedure in Form
Different objects have different properties
Full list of object’s properties can be seen in the Visual Basic Developer Studio
I’ll go over using the Developer Studio in the next lecture

21. Message Box
Remember when I said Form was “primary” means of communicating with user?
Message Box is other
Two forms:
MsgBox – Message to user (one-way)
InputBox – Ask for data from user (two-way)
Both forms are created with a function

22. MsgBox function
Causes a small popup window to appear in the middle of the screen
Has OK button for user to click to remove popup
MsgBox(<text>)
Example:
MsgBox(“Error! Wrong Data Type”)

23. InputBox function Causes popup window to appear in middle of screen
Contains a text box and OK button
Text parameter clues user into what to enter
User enters text and clicks OK
Function returns the text in text box
Example:
DIM Response As String
Response = InputBox(“Enter number of students”)

24. DoCmd object Performs actions that trigger events
Usually used to perform Form level actions
Like opening and closing forms
Can be used in any procedure
Example:
DoCmd.OpenForm “GetData”