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 VB Forms

        Form modules are the foundation of most visual basic applications. Inside form module, you can define the following

1.  Event procedures

2.  Form based declarations of variables and constants

Variables, constants several form events that you may need to consider are as follows

-        Initialize : event is called before the form is loaded

-        Load event : is called after the initialize event

-        Got focus event is called after that, It is called when user click the form or you load the form through code

-        Resize event is called when either user change the size of the form

-        Paint event is called when the form is redrawn

The most important properties of the form are listed in the following

Property name                      objective

Name                     used to represent name of form

Caption        string appear for the title of form

Back color     back ground color for form

Fore color     Color of text written on form

Font                Font style, type and size

Enabled         Enable or disable

Min button    =true

Max button     the minimize and maximize buttons are

                          Enabled

Hide                  To hide the form

Show                the show the form

Icon          change the icon on title bar of form

Private sub form_load

Form1.backcolor = QBcolor(12)

End sub 

Integrated Development Environment (IDE )

-        One of the most significant changes in visual basic is the integrated development environment (IDE)

-        IDE is the term commonly used in the programming world to describe the interface and environment that we use to create new applications

-        It is called integrated because we can access virtually all of the development tools that we need from one screen called an interface.

-        The IDE is also commonly referred to as the design environment or the program.

Menu / Tool bar: This is the only element of the IDE which is always visible. You use it to select which other IDE elements to view and to add forms or controls  to your project.

Tool box: The tool box is simply a library of controls which you can place on your application. Once you have placed all the controls you need onto your applications forms. You can hide the tool box to make room for working in the other elements on the IDE.

Project window

         This is simply a list of all the forms which make up your vb project. There are several kinds of forms.

Property window

          Most VB applications allow you to enter parameters which define how these controls work In Vb these parameters are called properties.

Forms: you add these to your VB application as they are needed. They are the windows which hold the various controls which make up your application.

Code window

        Like, it’s name implies, this is where you type in the code that VB executes. Notice that the heading of the window indicates with which event the code is executed.

Controls in Visual Basic 

Command button

        Command button appears in almost every program. Command buttons determines when the user wants to do something such as exit the application, you will perform these tasks to add a command button to an application.

1. Locate the size of the command button on the form

2.change the command button’s name and caption properties.

3.Add code to the command button’s click event procedure.

        Although the command button control supports dozens of properties, Although command button controls support over dozen events.

Property                       description

Back color           specified the command button’s

                              Background color

Caption        hold the text that appears on the command

Font         produces a font dialog box in which you can set

                  the caption’s font name, style and size

height       holds the height of the command button

mouse pointer     determines the shape of the mouse

                     cursor when the user moves the mouse over

                    the command button

tool tip    holds the text that appears as a tool tip at

                run time .

Sub command1_click()

Dim a, b as integer

a = inputbox (“enter a”)

b = inputbox (“enter b”)

if ( a > b ) then

   msgbox (“ a is biggest”)

else

msgbox (“ b is biggest”)

end if

end sub

 Text Box

           The text box is the standard control for accepting input from the user as well as to display the output. It can handle string and  numeric data but not images or pictures.

Private sub command1_click()

Dim sum as integer

Sum = val(text1.text) + val(text2.text)

Msgbox(sum)

End sub

The picture box

        The picture box is one of the control’s that is used to handle graphics. You can load a picture at design phase by clicking on the picture items in the properties window you can also load the picture at run time using the load picture method.

Picture1.picture = loadpicture(“c:\windows\mku.jpg”)

The image control

   He image control is another control that handles images and pictures. It functions almost identically to the picture box. However, there is one major difference the image is an image  but is stretchable, which means it can be resized. This feature is not available in the picture box. Similar to the picture box, it can also use the load picture

The list box

       The function of the list box is to present a list of items where the user can click and select the items from the list. In order to add items to the list, we can use the additem method.

Privare sub Form_load()

List1.additem(“sunday”)

List1.additem(“Monday”)

List1.additem(“Tuesday”)

List1.additem(“Wednesday”)

List1.additem(“Thursday”)

List1.additem(“Friday”)

List1.additem(“Saturday”)

End sub

The check box

         The check box control lets the user selects or unselects an option. When the check box is checked, its value is set to 1 and when it is unchecked , the value is set to 0. You can include the statements check1.value =0  to unmark the check box , as well as, use them to initiate certain actions.

Option button

         The option button control also lets the user selects one of the choices. However , two or more option buttons must work together because as one of the option buttons is selected, the other option button will be unselected. In fact only one option box can be selected at one time and when it is unselected, its value is set to false.

Sub command1_click()

If option1.value = true then

Form1.backcolor =vbred

Else if option2.value = true then

Form1.backcolor = vbBlue

Else

 Form1.backcolor = vbGreen

End if

End sub

DirList box

          The dirlist box means the directory list box. It is for displaying or list of directories or folders in a selected drive. When you place this control into the form and run the program. You will be able to select different directories from a selected drive in your computer.

DriveList box

          The drive list box is for displaying a list of drives available in your computer. When you place this control into the form and run the program

The File List box

          You can coordinate the drive list box, the directory list box and the file list box to search for the files you want

 

 

Msgbox and Input box  

      The msgbox function displays a message box and waits for the user to click a button and then an action is performed based on the button clicked by the user.

Msgbox(prompt,[button],[title])

Prompt –a string that is displayed as a message in the dialog box.

Buttons – specifies the type of buttons to display

Title: title bar of the dialog box

      The buttons parameter can take any of the following buttons

0 – displays ok button only

1 – Displays ok and cancel button

2- Displays abort, retry and ignore buttons

3-Displays yes, no and cancel buttons

4- Displays yes and no buttons

5- Displays retry and cancel buttons

16 vbcritical-displays critical message icon

32 vbquestion – displays  warning query icon

48 vbExclamation – displays warning message icon

64  vbinformation information message icon

      The msgbox function can return one of the following values which can be used to identify the button the user has clicked in the msgbox.

1 ok was clicked

2 cancel was clicked

3 abort was clicked

4 retry was clicked

5 Ignore was clicked

6 yes was clicked

7 no was clicked

Sub command1_click()

Msgbox(“welcome”)

Int a =msgbox(“Do you like blue color?”,3,”choose options”)

Msgbox(“the value of a is “ &a)

End sub

A message box is special type of visual basic window in which you can display a message to the user. You can display message, an optional icon, a title bar caption  and command button in  a msgbox.

Input box

        The input box function prompts the user to enter values, after entering the values, if the user clicks the OK button or presses enter on the keyboard. The input box function will return the text in the text box. If the user clicks the cancel button the function will return an empty.

Syntax

Inputbox ( prompt [.title] [, default])

Prompt – A string that is displayed  as a message in the dialog box

Title – a string expression displayed in the title bar  of the dialog box

Default – A default text in the text box that the user would like to be displayed

 

Sub command1_click()

Dim l as Double

Dim w as Double

Dim area as Double

l= inputbox (“enter length”)

w=Inputbox (“enter width”)

area = l * w

msgbox(area)

end sub

The input box () function is used to take the input from the user at run time.

 General syntax

Inputbox(prompt, title, default, xpos,ypos,helpfile,context)

Prompt – the message in the dialog box

Title – the title bar of the dialog box

Default-  string to be displayed in the text box on loading.

Xpos – the distance from the top of the screen to the top of the dialog box

        When you use input box() function, the program will show a simple window with a question for the user. The window will also have a place for the user to type in their answer, an OK button and a “cancel” button. If the user clicks the OK button any information typed into the text box will be sent back to your program. If the user clicks “cancel” key will return to your program without sending any information.

Private sub Command1_click()

Dim city as String

City = input box(“enter your city”, ”city question”)

Msgbox(city)l

End sub

Sub command2_click()

Dim a as integer

Dim b as integer

Dim c as integer

a = inputbox (“enter number1”)

b=inputbox(“enter number2”)

c= a + b

msgbox(c)

end sub

Font Dialog box and print Dialog box 

              Dialog box consist of a title bar, an optional main instruction, various controls in the content area, and command buttons. The font dialog box lets the user choose attributes for a logical font, such as font family and associated font style, size, effects. This dialog box can display the fonts supported by either printer or screen.

        Font bold: Bold is used to highlight the text and capture the reader’s attention

Font Italic: Letters slanted slightly to the right

Font strike thru : It implies the text is wrong

Font underline: Commonly used to help draw attention to text

Font name: Defining font style for text

Font size: refers to the height of a character

Each dialog box allows user to select his custom font setting like font name, font size, font color, font style, strike thru etc. To display the font display on the screen use show font method of the common dialog object.

Sub command1_click()

Dim i as integer

List1.addItem “times new roman”

List1.additem “arial”

List1.additem “sans serif”

List1.additem “ minion pro”

List2.addItem  “regular”

List2.additem “ bold”

List2.additem  “Italic”

List2.additem “ bold italic”

 

For i= 8 to 25 step 2

List3.additem i

Next i

End sub

Print dialog

        The print dialog control lets the user to print documents by selecting a printer and choosing which sections of the document to print. Allow you to specify the printer. If you don’t select a printer visual basic will print to the windows default printer.

Name – displays a list of available printers

Status – displays the status of the printer and whether it is ready to print.

Type – displays the type of printer

        Print dialog lets users select which printer to use for a print job and specify options for the print process. These options include specifying all pages, a range of pages, or the selection to print. There’s also an option to specify the number of copies to be printed, as well as an option to print to a file.

        The print dialog displays a dialog box that allows the user to choose printer settings for a document. The user can specify the printer to user, range of pages to print, and the number of copies.

        The print dialog box allows a user to select a printer if more than one is available. The user can decide either to print the whole document, to print a range of pages, or to print a portion of the document that was previously selected. The user can also decide on the number of copies to print from the document the range specified or the selected portion. Furthermore, the user can access the particular characteristics of the selected printer and specify how the printer should perform the job. If the selected printer can print in color and the document is in color but the user wants to print in black and white, he or she can specify this using the properties button.

 TOOL BOX

Control	Description
Pointer	Provides a way to move and resize the controls form
Picture Box	Displays icons/bitmaps and metafiles. It displays text or acts as a visual container for other controls.
TextBox	Used to display message and enter text.
Frame	Serves as a visual and functional container for controls
Command Button	Used to carry out the specified action when the user chooses it.
Check Box	Displays a True/False or Yes/No option.
Option Button	Option Button control which is a part of an option group allows the user to select only one option even it displays multiple choices.
List Box	Displays a list of items from which a user can select one.
Combo Box	Contains a Text Box and a List Box. This allows the user to select an item from the dropdown List Box, or to type in a selection in the Text Box.
HScroll Bar and VScroll Bar	These controls allow the user to select a value within the specified range of values
Timer	Executes the timer events at specified intervals of time
Drive List Box	Displays the valid disk drives and allows the user to select one of them.
Dir List Box	Allows the user to select the directories and paths, which are displayed.
File List Box	Displays a set of files from which a user can select the desired one.
Shape	Used to add shape (rectangle, square or circle) to a Form
Line	Used to draw straight line to the Form
Image	used to display images such as icons, bitmaps and metafiles. But less capability than the Picture Box
Data	Enables the use to connect to an existing database and display information from it.
OLE	Used to link or embed an object, display and manipulate data from other windows based applications.
Label	Displays a text that the user cannot modify or interact with.