Working with Intrinsic Controls and ActiveX Controls

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Introduction

Intrinsic Controls – the basic set of twenty controls in the toolbox.Are a part of the .exe VB program.

ActiveX Controls – exists as separate files.Files have a .ocx extension.

Introduction cont……….

Many routines and procedures are built into applications that are not designed for the end user.

Creating the Interface

Consists of sizing and locating the GUI and then adding the controls necessary for the user to use the form.

Form Size and Position

Height and Width property values can change the size of the form.

Top and Left property values change the position of the form.

AutoSize and BackStyle Properties

AutoSize – when set to True, the size of the control (label) will depend on the size of the caption property.

BackStyle – when set to Transparent, the color of the control below the label displays within the label’s border.

Copying Controls

You can copy and paste controls. A message will ask you if you want to

create a control array.Click “NO” if you just want a copy of the

control.We will work with control arrays later on.

ListBox and ComboBox Controls

Used to present the end user with choices from a list.

When a list is longer than the list box, scroll bars automatically appear.

ListBox and ComboBox

Control Appearance of List

Selection From List

ListBox List always shows, scroll bars added if list is longer than box.

Click item in list

ComboBox(Style = 0) Drop-down list Click item in list or type directly in box.

ComboBox(Style=1) List always shows, scroll bar added if list is longer than box.

Click item in list or type directly in box.

ComboBox(Style=2) Drop-down list Click item in list

Shape Control

Used to add shapes to the formSquareCircleRectangle

CheckBox Control

Used to turn controls on or off. Indicate the selection of deselection of

check boxes on a form.

Frame Control

Used as a container for other controls, such as option buttons.A frame can only have a rectangle shape.A frame can have a caption.When option buttons are added to the frame,

only one can be selected at a time.

Option Button Control

Presents a set of choices. Placed in groups, such as on a frame

control.Must be drawn directly on the frame to be a

part of the group.

CommonDialog Control

Allows you to add the Open, Save As, Color, Print and Font commands.

Not visible during run time. Activate the CommonDialog control by

using one of the Show methods.

Aligning Controls

Used to align controls in the form.VerticallyHorizontally

Format menu

Naming Controls

The name of a control is a property of a control.

Helps the programmer know what control he/she is working with when writing code.

Table 2-2

Writing Code

Project 2

Changing Control Properties

Basic Formatcontrolname.property = value

Variables

Temporary storage locations. Each variable has a

NameData Type – determines the type of data the

variable can hold.

Variables cont………..

Must follow these rules when choosing names for variables.The name must begin with a letter.The name cannot be more than 255

characters.Then name cannot contain punctuation or

blank spaces.

Declaring Variables

You must declare, or create, a variable.This will be done by Explicitly Declaring them.

Dim variablename As datatype

There can be a wide variety of different data typesByte, date, string, integer, variant, double

Assigning values to a variable

Variables can hold one value at a time. We use assignment statements to give

variables a value.dblRate = 10.5strName = “Mr. Preheim”

Variable Scope

Refers to whether or not the variable is visible to other sub routines.

Variables declared in a sub routine are not visible by other sub routines in the program.

Variables declared in the General Declarations are visible to all subroutines for that form.

Arithmetic Expressions

Code that contains statements to perform mathematical operations.

Order of Precedence – the order in which the calculation will take place.Can change the order of precedence by using

parentheses. Refer to table 2-7

Arithmetic Expression Examples

dblPayRate = dblHours * curWage dblTotal = intNumber1 + 100

If..Then…Else Statements

Used to execute one statement or another based on whether a condition is True or False.

A condition is made up of a 2 expressions and a comparison operator.=, <, >, <=, >=, <>

Key words in an If…Then…Else Statement If Then Else End If

If Statement Structure

If condition Then Block of code if the condition is TrueElse Block of code if the condition is FalseEnd If

If Structure Flowchart Example

Is Matinee Check Box

Checked

Price = 5 Price = 3.5

F T

If Structure VB Code Example

If chkMatinne.Value = 1 Then Price = 3.5Else Price = 5End IF

Constants

Similar to a variable in the idea that it uses space in memory.

However, the value of a constant does not change.

Defined by using the Const statement in the General Declarations.

Concatenation

The process of adding strings together is called concatenation.

Performed by using the ampersand (&) character.

Example:textRecord.Text = num & “ ” & cboShow.Text & vbNewLine

& txtRecord.Text

Items in a ComboBox

When items are added to a ComboBox, they are assigned an Index number.The first item is assigned an index of 0.

When an item is selected from the list during runtime, that index number is assigned to the ListIndex property.

Writing Code for the Common Dialog Control To display the Color dialog box, you will

apply the ShowColor method.