Introduction to Visual Basic.net 4

7/28/2019 Introduction to Visual Basic.net 4

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User Interface Design1


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DESIGNING USER INTERFACE

Control are added onto the form to enables users to interact

with the program.

Controls are added onto the form using Visual Basic 6.0ToolBox.

The user interface of a windows program usually includes :> Title or caption bar

> Menus

> Label boxes

> Text boxes> Buttons

> Windows

> Scroll bars 2


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TOOLBOX

Label

Frame

CheckBox

ComboBox

HScrollBar

Timer

DirListBox

Shape

Image

OLE

PictureBox

Textbox

CommandButton

OptionButton

ListBox

VScrollBar

DriveListBox

FileListBox

Line

Data

Diagram 1.0 : Toolbox

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Text Boxes

Use when you want the user to type some input or

display output.

Example :

Use Text Property.

Prefix namingtxt (txtTitle).

Text Box

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Program Code For Text Boxes

Example 1 :

lblName.Caption = txtName.Text

* Input from user enter into the text box is assigned tothe caption property oflblName.

Example 2 :

txtMessage.Text = Watson, come here

*Display text in a text box during program execution,

assign a literal to the Text property.5


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Frames

Use as containers for othercontrols.

Example :

Groups of option buttons or check boxes.

Make form easierto understand.

Prefix namingfra (fraColor).6


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Check Boxes

Allow the user to select (or deselect) an option.

Example :

In any group of check boxes, any numbermay beselected.

Value property of a check box is set to 0 ifunchecked, 1 ifchecked, or2 ifgrayed (disabled).

Prefix namingchk (chkBold).7


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Program Code For Check Boxes

* Set the initial value for check boxes :

Example 1 :

chkBold.Value = 1 Make box checkedchkBold.Value = 0 Make box unchecked

Example 2 :

chkBold.Value = Checked Make box checkedchkBold.Value = Unchecked Make box unchecked

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Option Buttons

Use when only one button of a group may beselected.

Example :

Value property of an option button is set to True if

selected or to False ifunselected. Prefix namingopt (optRed).

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Locate The Option Button

Any option button placed directly on the form (not in

a frame) function as single event.

A group of option buttons inside a frame functiontogether.

* The best method is to first create a frame and then create each option

button inside the frame.

* Must be careful to create the button inside the frame, dont create it

on the form and drag it inside the frameits still belongs to the

forms group, not the frames group.

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Program Code For Option Button

* To make an option button appear selected initially :

Example :

optRed. Value = True Make button selected

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Images

Control holds a picture.

Enable to set an images Picture property to a file

with an extension of.bmp, .wmf, .ico, .dib, .gif, .jpg,

.emf, or.cur.

Set Stretch property to True to make the picture

enlarge to fill the control.

Set Visible property to False to make the image

disappear.

Prefix namingimg (imgPicture).

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Program Code For Images

* Make an image invisible at rum time.

Example :

imgLogo.Visible = False

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Setting a Border and Style

Most controls can appear to be 3-dimensional or

flat.

Labels, text boxes, check boxes, option buttons and

images all have an Appearance property.

0 Flat or 1 3D.

* To make a label or an image appear 3D, you must give it a

border.

* Set the BorderStyle to 1 Fixed Single.

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Shape Control

Place shapes on a form :

i) Rectangle

ii) Squares

iii) Ovals

iv) Circles

Example :

Prefix namingshp (shpCircle). 15


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Shape property

Determine the shape by setting its Shape property :

0 - Rectangle

1 - Squares2 - Ovals

3 Circles

4 Rounded Rectangle

5 Rounded Squares

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Line

Draw line on a form.

Example :

Prefix naminglin (linLogo).

Line

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ADDING CONTROLSONTHE FORM

To use a control, double click on the specific control

on the toolbox.

You can control the number of objects in theToolbox but VB provides 20 intrinsic controls in the

toolbox.

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DETERMININGTHE PROPERTIES

Different controls have different set of property. Due

to some controls that have long list; the Properties

Windows have a scrollbar to move through the long

list.

You need not to define every single property for the

controls. You only have to change what is required

for the application designed. Visual Basic has set

all of the properties to its default value.

You only need to change the value when you wantit to be different from its default.

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NAMING CONTROLS

Visual Basic provides a unique name for thecontrols such as Label1, Label2, Text1 andCommand1.

The names are the controls names. Each controlhas a unique name that distinguishes it from othercontrols from the same object.

For example, the The Average of Two Numbersapplication has more than one TextBox control.

It is important to distinguish each Textbox on theform.

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DELETINGTHE CONTROLS

If you wish to delete any of the controls from the

form, you may do so at design time.

Follow the steps in the box.

i) Point the cursor on therequired control, which is

on the form.

ii) Click on the control and

hit the DELETE key.

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Activity 1

Your Name

Message

Red

Green

BlueBlack

COLORBold

Italic

Underline

STYLE

Display

Clear

Print

Exit

Follow the sketch below to create the form :

ImgLittle lblMessage

ImgBig

fraColor

optRed

optGreen

optBlue

optBlack

fraStylechkBold

chkItalic

chkUnderline

fraText

txtName

txtMessage

cmdDisplay

cmdClear

cmdPrint

cmdExit 22


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Thank You

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Introduction to Visual Basic.net 4