copyright © don kussee 1120-ch2 #531 cns 1120 chapter 2 project structure and tools 1120-ch2.ppt

Copyright © Don Kussee 1120-Ch2 #53

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CNS 1120Chapter 2

Project Structure and Tools1120-Ch2.PPT

2Copyright © Don Kussee 1120-Ch2 #53

Structure of VB projects

ProjectResource

fileClass

modules*Code modules

Forms

Generaldeclarations

sectionGeneral

subprocedures

Controls

Properties Eventprocedures

Generaldeclarations

sectionGeneral

subprocedures

* The structure of class modules has been omitted for clarity.

0+

1

0 or 1

0+ 1+

1+ 0+

0+0+

0+1


Structure of VB projects

ProjectForms

Generaldeclarations

sectionGeneral

subprocedures

Controls

Properties Eventprocedures

0+

10+ 1+

1+ 0+

Displayed “windows”

User interface object

Instructions to the computer

The definition of what isincluded in the program.

Code


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Terms

• Project - all of the Forms, controls, code necessary for a program to run.

• Form - the screen we will design on, and the user will see.

• Controls or Objects - GUI objects attached to the form

• Expressions - code - the instructions that the computer will follow.


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TOPE chartTask-Object-Event

• Task Object Property Event


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VB Programming Process

1 Understand the user’s requirements2 Analyze - TOPE chart for inputs & outputs3 Develop the GUI forms to be used

– Place the controls on the forms4 Write code to hook the controls together5 Test and debug the program6 Create the executable program.


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Visual Basic Modes• Design

– where most of our time will be spent – Form, the tool bar and tool box are available– Properties window is available– Code window is available

• Run - where we will test & evaluate the program • Break - where we can debug our problems• Compile

– The program we will give to the user.


The VB environment

Form frm 53 Properties, 31 Events, 21 Methods


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53 Properties Propertiesfrm


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FormEvents

31 Events


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Form methods 21 Methods

• Circle, Line, Point• Cls, Hide, Show, Refresh• Popup menu • Drag, DragOver• Move left, [top, [width, [height]]]• SetFocus, GotFocus, LostFocus


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Properties of Forms

• Caption - Name at the top of the form• BackColor - Systems colors or Palette• WindowState - 0 = Just like design(Default)

1 = Minimized, 2 = Maximized• Name used in code also is default file name• Form1.BackColor = vbRed• Form1.Label2.Forecolor = vbRed


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Objects, Classes, Controls

• Over 4000 different controls available - we will use about 10

• Many special VBX on the internet• NextPage Corp’s VBX is $ 5,000• VB assists in building of new Classes -

ActiveX - VBX - OCX• CNS 3200 includes these concepts


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Controls, Objects, Classes

Text Box

Control Button

Label


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Programs

• Series of steps for the computer to follow• Computer can be told to do only 5 things

– Input - Get data from outside– Output - Supply data to outside– Process - Add, Subtract, Multiply, etc– Select - Equal to, less than, between – Loop - Repeat some steps of a program


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Controls, Objects, Classes

• Label output• Text Box input• Command Button trigger

• Pickup truck - Red Dodge V-10 long bed• Bird - Gray - “chi-cog-o” - top-feather - walks• Computer- 300 Mhertz- 64M RAM- 17” screen


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Controls7 general categories

• Trigger 3 Timer, Command button• Input 6 TextBox, Combo, Scroll• Output 4 Label, Textbox, Image• Organize 3 Form, Frame• Graphic 2 Line, Circle• Data Access 4 Combo, Data• Integration 1 OLE


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Primary Controls for Input…………... Output………...

• Text box• Command button• MsgBox / InputBox• Menu• Check box• Option buttons• List / Combo box• Scroll bars

• Text box• MsgBox• Label• Image• Picture


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Controls - Object - Class

• Properties that can change it’s appearance– Size, shape, location, look, color

• Events that it can respond to– Click, mouse over, drag

• Methods - things it can do– Move, Connect, Load, Update


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Real world objectsproperties, events, methods

• Cashier• Woodpecker• Grass• Computer• Student• Professor• Dog Vs Cat• Airplane

• Jet ski• Bicycle• Bicycle rider• Olympic Bicycle racer• Car• Duck• Ostrich• Duckbilled platypus


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VB Tool BoxLabel tool

Used to label other controls, and provide output.


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Label lbl

• 48 Properties– Appearance & location

• 23 Events– Change– Click– DblClick– Load

• 10 Methods– Move– Refresh– ZOrder


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Label


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Label properties

• Name - used in code procedures• Caption - displayed on the form or control

• Enabled - does it work• Visible - can you see it

• Usual event - None


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Command Button cmd

• 17 Events – Cause an user event to occur - Click usually

• 24 Methods• 32 Properties for each instantiation

– Appearance• Size, Shape, Location, Colors, Font, Style

– Caption - The title on the button– Picture property - an image on the button


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Command Button properties

• Name - used in code procedures• Caption - displayed on the button• Picture - displayed on the button• Enabled - does it work• Visible - can you see it

• Usual event - Click


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CommandButton.Caption changed


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Events


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Processing code for Command Button

• Note: header and indentation


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Header required for every program

Rem *********************************

Rem *** Program name ***‘ *** Programmers name ***‘ *** Date of program ***‘ *** Description of the program ***‘ ********************************


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Demo of design mode

• Add a control 3 ways– Double click, Draw, Copy & Paste

• Delete control• Change properties 3 ways F4

– Type over– Additional menu …– Choice items


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Procedure Vs Event programming

• Procedures ... the old way, it starts at the top and runs to the bottom every time - how a traffic light works, cars or no cars

• Event new way store clerks - demand– The program waits, then reacts to some event. – Reacts differently to different events.– Event procedure is the detail code for the

computer to follow


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Other VB Windows

• Form Layout Window Figure 2.25• Project Explorer Window Figure 2.26• Help Windows Figure 2.29 - 32


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Stopping Visual Basic

• Include an Exit key in every project• Ctr + Break will stop processing• Run menu Square• Alt + R Gets run menu - choose E


The VB environment

PropertiesThe currently selected control is named Command1

The setting for Command1’s Caption property is Command1

Property list

Object box


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Code window

Procedure boxObject box

Code area


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Code Window

• Each procedure has an Object_Event


The VB environment

Menu barTool bar

Toolbox

Code window

Form window Properties window

Project window


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Naming objects

• When projects get big (Project 2 Page 59 uses 17 labels) naming objects with meaningful names is very helpful when writing code and provides documentation.

• Not all objects need to be re-named• All object names should use the three letter

abbreviation of the object type


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Some primary controls• Command button - allows user to cause event

– 32 properties 24 Methods 17 events cmd• Form - The window that the user sees

– 52 properties 21 Methods 31 events frm• Label - outputs information to the user

– 48 properties 10 Methods 18 events lbl• Timer - an event based on time

– 7 properties 0 Methods 1 event tmr


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Some primary controls• Frame - groups controls into a group

– 34 properties 6 Methods 13 events fra


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Command Button properties

• 32 Properties 24 Methods 17 Events• Name - used in code procedures• Caption - displayed on the button• Picture - displayed on the button• Enabled - does it work• Visible - can you see it• Usual event - Click


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Printing Visual Basic programs


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File Names

• Win95 allows 256 characters – Except only ~ ? * :– But in DOS mode only 1st 6 letters are used– There is an extension

Form including controls and code .FRM Changes to controls on the

form .FRX Project listing forms and others files .VBP


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Win95 Standard File Extensions

• VBP VB Project• FRM VB Form• VBX controls on form• BAS VB Module• CLS VB Class• MDB MS Access• TXT Generic text• EXE Executable

• DAT Data • LOG Recorded event• COM Commands• BAT Batch • BIN Binary • BAK Backup• JPG Graphics• SYS System


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Saving Visual Basic Programs

1 Create a folder with a descriptive name2 In the folder, create a VB program3 Save the Form, Classes, Code, Resources4 Save the Project

• Save frequently• Backup often


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Saving Visual Basic Programs


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File type change


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Expanded VP program parts

• Projects - grouping of forms & files & code• One and only one project .vbp• Zero or more Forms - usually one .frm

– modification of controls on the form .vbx• Zero or more Code modules -often zero .bas• Zero or more Class modules -often zero .cls• Zero or more Resource files -often zero .res


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Assignments

• Lightening 1• Exchange Rate• Café Don• Lightening 2• Color choice• Data types


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Computer Terms

• Syntax• Semantic• Keyword• Code• Control• Object• Properties• Methods• Events

• Run time error• Syntax error• Logical error• Default value• Form• lbl Prefix• cmd Prefix• Empty string

copyright © don kussee 1120-ch2 #531 cns 1120 chapter 2 project structure and tools 1120-ch2.ppt

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