1. Programming In Visual Basic.NET
Chapter 3.1 Controls
Programming In
Visual Basic.NET

2. Controls in the Toolbox
Those controls that we will use in this class.

3. The Name Property How the programmer refers to a control in code
Name must begin with a letter
Must be less than 215 characters long
May include numbers and the underscore
Use appropriate 3 character naming prefix

4. Control Name Prefixes

5. Text Box (txt) Used for user input/data entry Text Property
What is displayed in text box
What user entered in text box
TextAlign Property
Controls alignment of text in the Text Box
Change Event 7

6. TextBox Control – Properties
BorderStyle - defines the border surrounding the text box
ForeColor, BackColor - defines the text color and background color respectively
Enabled - controls whether the text box can get focus and will respond to events
Locked - controls whether user can change the text appearing in the text box
MultiLine - controls whether text will appear on multiple lines
MaxLength - defines the maximum number of characters that the user can enter into the text box

7. TextBox Control – Properties
Name - defines name used to reference control instance with code
Again, use a standard prefix of "txt"
ScrollBars - defines whether vertical or horizontal scroll bars appear in text box
Text - contains the text appearing in text box
TextAlign - justifies text within the visible region of the control instance
X, Y, Height, Width properties define the position and size of the control instance

8. TextBox - Methods and Events
Focus method sets input focus to a text box
Enter event fires when text box gets focus
Leave event fires when text box loses focus
TextChanged event fires when the the textual contents change at run time
The event fires for each character typed

9. Button (btn) Used to run/activate an Event Procedure Click event
Properties
Text – Change the text property to display text to user
Image – change image to use a graphic button
Forecolor – changes the color of the text displayed
Backcolor – changes the color of the button 5

10. Label (lbl) Used for Cannot by modified by user Output on a form
Identification of objects
Directions/Information
Cannot by modified by user 6

11. Label Properties
Text – used to display text or instructions to the user
Font – change font size, color, appearance
Image – use images to draw attention
Autosize – adjust the label object to text entered into the text property
textAlign – aligns the text displayed on the object

12. Group Box (grp)
Used as containers for other controls such as radio buttons and check boxes
Improves readability of form
Text Property
What is displayed on the top edge of the group box
Splits the form object into separate planes
allows several groups of radio buttons on one form. 7

13. Group box (grp)
Group boxes must be added to the form before other objects are added to them.
You can not drag checkboxes or radio buttons from the form to the group box
The group box must have the focus of the cursor before you draw your other objects inside them
Editing handles must be visible

14. Check Box (chk) Used for user input/data entry
Allows the user to select or deselect 1 or more in any group
Checked Property
Checked = True
Unchecked = False
CheckChanged Event – default event 10

15. Radio Button (rdo) Used for user input/data entry
Allows the user to select only 1 in any group
First create a group and then create each radio button inside the group
Checked Property
Checked = True
Unchecked = False
CheckChanged Event – default event 9

16. Picture Box (pic) Displays/contains a picture/graphic Image Property
Complete path and filename of graphic
.bmp, .gif (including animated), .jpg, .png, .ico, .emf, .wmf
SizeMode Property
StretchImage causes graphic to be resized to match the size of the control
Visible Property 11

17. Other Properties BorderStyle Property –None, FixedSingle, Fixed3D
Forecolor – changes the color of text inside object
Backcolor – changes the color of object
Textalign – aligns text property
Enable
true (user can activate the object),
false (object us not available to user)
Visible
True (object appears on form)
False (object is hidden at run time)
TabIndex – set the order of the focus for controls on the form 14

18. Properties and Methods
Properties can be set at design time in the property box
Or they be changed during program execution by statements in your code
txtHours.Text = "“ ‘ clears the content
Methods are action performed on objects
txtHours.focus

19. Selecting Multiple Controls
SHIFT-Click or CTRL-Click to select/deselect multiple controls
Use the mouse to drag a selection box around multiple controls
To deselect all selected controls click elsewhere on the form 15

20. Selecting Multiple Controls (cont.)
Start
here
Drag
to here
Using mouse to drag a selection box around multiple controls
Multiple selected controls,
observe selection handles.

21. What Can be Done with Multiple Selected Controls?
Use Format Menu or Layout Toolbar to
Align them to each other
Make same size
Modify the spacing between them
Move them as a group
Set their common properties

22. Designing the User Interface
To the user the Interface should be
Easy to understand
Familiar
Comfortable
Organized
Sans Serif Fonts are best, not boldface or large
Color Neutral Overall
Keyboard Accessible

23. Keyboard Access Keys Also referred to as Hot Keys Underlined Letter
User presses ALT + underlined letter
Use Windows-Standard Keys
Defined using Text Property
Text=&OK
Text=E&xit 17

24. Default & Cancel Buttons
Default Button
Identified visually on Form by its darker outline
Responds to ENTER key
Form's AcceptButton Property
Cancel Button
Responds to ESC key
Form's CancelButton Property

25. Focus One control on a Form always has the Focus
Not all control types can receive the focus
TabStop Property (applicable only for controls that are capable of receiving the focus)
Designates whether a control is allowed to receive the focus; True or False

26. Tab Order
User should be able to use TAB key to move the focus through a form in an organized manner; top to bottom, left to right
TabIndex Property
Number in tab sequence
0 for first control to receive the focus when the form loads
In form’s graphic view – Use View Menu, Tab Order to set 18

27. Setting TabIndex Property
View menu, TabOrder
Click on each control in sequence to set TabIndex property of controls automatically

28. Form's Screen Location StartPosition Property Manual CenterScreen
WindowsDefaultLocation
WindowsDefaultBounds
CenterParent

29. ToolTips
Small label that is displayed when user places pointer on a control and pauses
Usually used with Command Buttons
Steps for creating ToolTips
Add a ToolTip Control to Form
Appears in the Component Tray, pane at bottom of Form Designer where nondisplay controls are shown
Set ToolTip on ToolTip1 Property of each control to the text of tip 19

30. ToolTip Control
Component Tray

31. Clearing Text Boxes & Labels
Set Text Property equal to the Empty String
Empty String is 2 quotation marks with no space between them ("")
Use the Clear Method of a Text Box
txtName.Text = ""
lblMessage.Text = ""
txtCourse.Clear( ) 20

32. Resetting the Focus Places the Insertion Point in a Text Box
Use the Focus Method
txtName.Focus( ) 21

33. Checked Property of Check Boxes and Radio Buttons
Selects/Deselects Check Box or Radio Button
Set Checked Property
True = Checked, selected
False = Unchecked, deselected
radRed.Checked = True
chkBold.Checked = False 22

34. VB Color Constants ForeColor and BackColor Properties
Use VB Color Constants from the Color Class
View complete list in Help by using the keyword Color followed by a period
txtName.ForeColor = Color.AliceBlue
lblMessage.BackColor = Color.White 23

35. With and End With Change several properties at once in Code
Will run more efficiently
With txtName
.Visible = True
.Text ="Lynne"
. Focus( )
End With 24

36. Concatenation Think of it as "glueing" text strings together
Example: txtFName contains First Name txtLName contains Last Name
lblFullName.Text = txtFName.Text & " " & txtLName.Text
lblNote.Text = "Today's weather is " & txtWeather.Text & "." 25

37. Continuing Lines of Code
For long lines of code it is more readable to continue them to the next line
At the end of the line type Line Continuation Character, a Space followed by an Underscore
lblMessage.Text = txtFName.Text & "" & txtLName.Text & _
", welcome to Aiken Technical College. Today is " & _
txtToday.Text 26