Intrinsic and ActiveX Controls
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Transcript Intrinsic and ActiveX Controls
Working with Intrinsic
Controls and ActiveX
Controls
Project 2
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,
Click item in list
scroll bars added if list
is longer than box.
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 form
Square
Circle
Rectangle
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.
Vertically
Horizontally
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 Format
controlname.property
= value
Variables
Temporary storage locations.
Each variable has a
Name
Type – determines the type of data the
variable can hold.
Data
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 types
Byte,
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
= 10.5
strName = “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 True
Else
Block of code if the condition is False
End If
If Structure Flowchart Example
F
Price = 5
Is Matinee Check
Box
Checked
T
Price = 3.5
If Structure VB Code Example
If chkMatinne.Value = 1 Then
Price = 3.5
Else
Price = 5
End 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.