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What is Visual Basic?

Visual Basic is a programming language that allows you to create your own software with the look of Windows programmes that you are familiar with. It is the most common and easiest to learn of modern computer languages

Visual Basic is also able to add additional features to Microsoft Office applications.  When you write a Macro in Excel it is actually created for you using Visual Basic.

The word visual in Visual Basic means graphical, easily seen such as pictures and symbols that you can click on and drag.

BASIC is short for Beginners All purpose Symbolic Instruction Code. BASIC was originally developed to make it possible for home users to program PCs.

BASIC is considered to be a high level language because BASIC code uses a simple set of English words and symbols to give instructions to the computer, not the low level instructions that deal with the zeros and ones that the computer understands.

Visual Basic is also an Event Driven language.  Event driven languages allow you to choose what you do rather than have to respond to a series of questions the computer dictates. Event driven languages such as Visual Basic are called Object Oriented Languages or OOLs.

There are two parts to creating Visual Basic applications. 

1.       You firstly place the objects (buttons etc) on a form then

2.       Secondly write the code that is hidden behind these buttons. The code makes the buttons respond in the way you want them to.

Variables

Variables are placeholders used to store values; they have names and data types. The data type of a variable determines how the bits representing those values are stored in the computer's memory. When you declare a variable, you can also supply a data type for it. All variables have a data type that determines what kind of data they can store.

You can think of variables as containers, and you choose to put data in the most suitable container. You would not put a small object in a large box or try to stuff a large object into a small box.

The following variables are available in visual basic.

Variable Data Types

Data type	Prefix	Example	What the data is used to hold	Bytes
Boolean	bln	blnWillgo	True or False
Byte	byt	bytRasterData	Whole numbers from 0–255	1
Currency	cur	curMoneyspent	Money values, has a fixed decimal point
Date (Time)	dtm	dtmStartwork	Date
Double	dbl	dblTolerance	Large decimal numbers more accurately	8
Integer	int	intQuantity	Smaller whole numbers –32,768 to 32,767,	2
Long	lng	lngDistance	Whole numbers that are very large	4
Single	sng	sngAverage	Decimal number	4
String	str	strFName	Any collection of keyboard characters but usually words
Variant	vnt	vntCheckSum	Stores all the above data types but is slow and wasteful of memory	16

Here is how you would declare a variable

Dim curMoneyspent As Currency

The cur is the abbreviation for currency. This is a naming convention that helps you by letting you know the type of data that is attached to a particular variable. 

What are Labels?

Programmers use labels to place titles around the form and to label text boxes so users know what to type into the text box. When you use the Label control, your code can change the label's text so that different messages can appear when needed.

When you place labels on a form, you'll almost always set the Label control's Name property and type a new Caption value. In addition, you'll want to change the Font property and possibly the label's color and style.

Below are the most common Label control properties that you'll set as you work with the Label control.

Common label properties.

Property	Description
Alignment	Determines whether the label's caption appears left-justified, centered, or right-justified within the label's boundaries.
AutoSize	Enlarges the label's size properties, when True, if you assign a caption that is too large to fit in the current label's boundaries at runtime.
BackColor	Specifies the label's background color. Click the BackColor's palette down arrow to see a list of colors and click Categorized to see a list of common Windows control colors.
BackStyle	Determines whether the background shows through the label or if the label covers up its background text, graphics, and color.
BorderStyle	Determines whether a single-line border appears around the label.
Caption	Holds the text that appears on the label.
Enabled	Determines whether the label is active. Often, you'll change the Enabled property at runtime with code when a label is no longer needed.
Font	Produces a Font dialog box in which you can set the caption's font name, style, and size.
ForeColor	Holds the color of the label's text.
Height	Holds the height of the label's outline in twips.
Left	Holds the number of twips from the label's left edge to the Form window's left edge.
MousePointer	Determines the shape of the mouse cursor when the user moves the mouse over the label.
TabIndex	Specifies the order of the label in the focus order. Although the label cannot receive the direct focus, the label can be part of the focus order.
ToolTipText	Holds the text that appears as a tooltip at runtime.
Top	Holds the number of twips from the label's top edge to the Form window's top edge.
Visible	Determines whether the label appears or is hidden from the user.
Width	Holds the width of the label in twips.
WordWrap	Determines whether the label expands to fit whatever text appears in the caption.

What are Text Boxes?

Text boxes accept user input. Although several other controls accept user input, text boxes are perhaps the easiest to set up and respond to. In addition, a text box is simple to use, and people see text boxes on Windows forms all the time.

The table below lists the common properties associated with text boxes. By familiarising yourself with the properties now, you will be able to more quickly produce applications as you learn more about Visual Basic.

Common text box properties

Property	Description
Alignment	Determines whether the text box's text appears left-justified, centered, or right-justified within the text box's boundaries.
BackColor	Specifies the text box's background colour. Click the BackColor property's palette down arrow to see a list of colours and click Categorized to see a list of common Windows control colours.
BorderStyle	Determines whether a single-line border appears around the text box.
Enabled	Determines whether the text box is active. Often, you'll change the Enabled property at runtime with code when a text box is no longer needed.
Font	Produces a Font dialog box in which you can set the Text property's font name, style, and size.
ForeColor	Holds the color of the text box's text.
Height	Holds the height of the text box's outline in twips.
Left	Holds the number of twips from the text box's left edge to the Form window's left edge.
Locked	Determines whether the user can edit the text inside the text box that appears.
MaxLength	Specifies the number of characters the user can type into the text box.
MousePointer	Determines the shape of the mouse cursor when the user moves the mouse over the text box.
MultiLine	Lets the text box hold multiple lines of text or sets the text box to hold only a single line of text. Add scrollbars if you wish to put text in a multiline text box so your users can scroll through the text.
PasswordChar	Determines the character that appears in the text box when the user enters a password (keeps prying eyes from knowing what the user enters into a text box).
ScrollBars	Determines whether scrollbars appear on the edges of a multiline text box.
TabIndex	Specifies the order of the text box in the focus order.
TabStop	Determines whether the text box can receive the focus.
Text	Holds the value of the text inside the text box. The Text property changes at runtime as the user types text into the text box. If you set an initial Text property value, that value becomes the default value that appears in the text box when the user first sees the text box.
ToolTipText	Holds the text that appears as a tooltip at runtime.
Top	Holds the number of twips from the text box's top edge to the Form window's top edge.
Visible	Determines whether the text box appears or is hidden from the user.
Width	Holds the width of the text box in twips.

What are Form Properties?

Forms have properties that you can and should set when you create an application. Being the background of your application, the form's properties help set the stage for the rest of the project. The form supports more property values than the other controls described here, but the list below lists only the most common properties that you'll need.

New Term: Pixel stands for picture element and represents the smallest addressable graphic dot on your monitor.

Common form properties.

Property	Description
BackColor	Specifies the form's background color. Click the BackColor's palette down arrow to see a list of colors and click Categorized to see a list of common Windows control colors.
BorderStyle	Determines how the Form window appears. The BorderStyle property specifies whether the user can resize the form and also determines the kind of form you wish to display.
Caption	Displays text on the form's title bar at runtime.
ControlBox	Determines whether the form appears with the Control menu icon. The Control menu appears when your application's user clicks the Control menu icon.
Enabled	Determines whether the form is active. Often, you'll change the Enabled property at runtime with code when a form is no longer needed. Generally, only multiform applications, such as MDI applications, need to modify a form's Enabled property.
Font	Produces a Font dialog box in which you can set the text's font name, style, and size.
ForeColor	Holds the color of the form's text.
Height	Holds the height of the form's outline in twips.
Icon	Describes the icon graphic image displayed on the taskbar when the user minimizes the form.
Left	Holds the number of twips from the form's left edge to the screen's left edge.
MaxButton	Specifies whether a maximize window button appears on the form.
MinButton	Specifies whether a minimize window button appears on the form.
MousePointer	Determines the shape of the mouse cursor when the user moves the mouse over the form.
Moveable	Specifies whether the user can move the form at runtime.
Picture	Determines a graphic image that appears on the form's background at runtime.
ScaleMode	Determines whether the form's measurements appear in twips, pixels (the smallest graphic dot image possible), inches, centimeters, or other measurements.
ShowInTask bar	Determines whether the form appears on the Windows taskbar.
StartUpPosition	Determines the state (centered or default) of the form at application startup.
Top	Holds the number of twips from the form's top edge to the Form window's top edge.
Visible	Determines whether the form appears or is hidden from the user.
Width	Holds the width of the form in twips.
WindowState	Determines the initial state (minimized, maximized, or normal) in which the window appears at runtime...........

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