Visualbasic 6.0
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Visual Basic 6.0 Mr. Jose Marie M. Pacia
VISUAL BASIC 6.0©
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Object Oriented Programming • uses "objects" and their interactions to design applications and computer programs • Programming techniques may include features such as encapsulation, modularity, polymorphism, and inheritance VISUAL BASIC 6.0©
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Encapsulation • principle of information hiding • the hiding of design decisions in a computer program that are most likely to change
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Modularity • software design technique which software is composed from separate parts, called modules
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Polymorphism • is the ability of objects belonging to different types to respond to method calls of the same name, each one according to an appropriate type-specific behavior. • controlling code can issue the same command to a series of objects and get appropriately different results from each one. VISUAL BASIC 6.0©
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Inheritance • is a way to form new classes (instances of which are called objects) using classes that have already been defined. • The new classes, known as derived classes, take over (or inherit) attributes and behavior of the pre-existing classes, which are referred to as base classes (or ancestor classes).
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Getting Started with VB6 • Menu bar – a special kind of control that lets the users select options and issue commands • Tool Bar – toolbar is a panel on which onscreen buttons, icons, menus or other input or output elements are placed
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• Toolbox - A collection of tools that act as storage area of controls you can place on your form. • Form window – a window you customize to create the user interface of your program
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• Project window – lists its components in a tree structured listing. Related objects appear together. • Properties window – a list of property of every control • Project – a collection of file that make up your application
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Getting Started 1. Open visual basic (Start > All programs > Microsoft Visual Studio > Microsoft Visual Basic 6.0 2. On the new project dialog box select standard exe to create a new program then click open VISUAL BASIC 6.0©
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Saving a Project 1. On the menu bar, click File > Save project. 2. Save every form and modules on your project in the same directory.
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Events • An activity that occurs during a program’s execution, such as a mouse click or a keystroke
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Most Use Events • Activate – executes when form is activated or in focus • Click – executes when a certain object is click by a mouse • Load – executes when a certain object is loaded or run for the first time VISUAL BASIC 6.0©
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• Unload - executes when a certain object is un loaded or terminated • Mouse Move – Executes when a mouse is move
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Form • Correspond with other controls • The main window of the program when run • Form Properties – – – –
Border Style Window State Caption Picture
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Changing properties during runtime Form1.BackColor = &H80FFFF Form1.Caption = “this change during runtime”
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Objects on Visual Basic • Label Box – control use to display text • Label Properties are: Alignment, Appearance, AutoSize, Fore Color, Caption
– Properties can be change on the properties window
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Code Label1.caption = “” ‘clears the text of a label Label1.caption = “This is a label” Label1.font = tahoma Label1.fontsize = 12 VISUAL BASIC 6.0©
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Command Button • is a widget that provides the user a simple way to trigger an event • Executes when triggered or clicked – – – –
Appearance Picture Style Caption
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Event • Click • DblClick
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Code • Command1.caption = “Save” • Command1.visible = false
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Text Box • Used to display information entered at design time or runtime. This is used to ask a user an input – – – – – – – –
Appearance BorderStyle Font Locked Maxlength Multiline ScrollBar Text
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Code • Text1.text = “” • Text1.locked = true • Text1.visible = true
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Visual Basic Operator • • • • • • •
^ - Exponent * - Multiplication / - Division + - Addition - - Subtraction Mod – Integer & - Concatenation
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Code • Text1.text = val(text1.text) + val(text2.text)
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Lab Exercise 1 • Create a simple payroll system which computes the basic salary of an employee – Example1
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Option Button • An object which allows the user to choose options or choices
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Properties of Option Box • Caption – Text displayed on option Button • Value – Can be True or False
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Combo Box • An object which allows the user to choose options or choices but in a drop down list
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Properties of a Combo Box • List – use to insert all the choices on your combo box • Text – the selected value or text • Style – type of a combo box (0Dropdown Combo, 1-Simple Combo, 2-Dropdown Combo) VISUAL BASIC 6.0©
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Methods • Actions can be triggered on an object • Example are: additem, clear ect.
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Adding Items on Combo on runtime Combo1.AddItem "Choice 1" Combo1.AddItem "Choice 2“ Clearing the items Combo1.clear VISUAL BASIC 6.0©
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Decision Making • If/then – Allows a program to make a decision based on the truth or falsity of some expression – It is a condition VISUAL BASIC 6.0©
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If then / else • Allows a user to make a decision but has two default decision
If then/ elseif /else • For two or more choices VISUAL BASIC 6.0©
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Logical Operators • • • • • • • •
> - Greater Than < - Less Than >= - Greater Than Equal <= - Less Than Equal <> - Not equal = - Equal And – Two Conditions that should be true Or – Two conditions that at least one condition can be true
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Code If Combo1.Text = "A" Then MsgBox "A" Else MsgBox "NOT A" End If VISUAL BASIC 6.0©
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Lab Exercise 2 • Click Here
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Date and Time • Date Function – Format(Date,”MMM DD, YYYY”)
• Time Function – Format(Time,”HH:MM:SS am/pm”)
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ImageBox • Insert image on your form • LoadPicture(“”) is use to load a picture on runtime
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Properties • Stretch
– True – Picture will adjust according to the size of your picture box – False – Picture will load on its normal size
• Picture
– Specify the picture or target picture
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Code • Image1.Picture = LoadPicture("C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures\Sunset.jpg")
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Timer • Label1.Caption = Format(Time, "HH:MM:SS")
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MsgBox • Shows a pop up dialog box and informs the user • MsgBox "Prompt", button, "TitleBar"
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Sample Button • Vbinformation – Ok and Information Icon • VbYesNo – Yes and No Button • VbCritical – Critical Icon and Ok Button • Etc…
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Declaring a variable Dim – Dimension/use to declare a variable Dim lagyu As String
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Data Types • • • • • •
Boolean – true or false Char – One Unicode character Byte – 0 to 255 Date – Dates Decimal – 1.0E-28 to 7.9E+28 Short - -32,768 to 32,767
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• Integer - -2,147,483,648 to 2,147,483,647 • Long - -9,223,372,036,854,775,808 to 9,223,372,036,854,775,808 • Single - +1.5E-45 to +3.4E+38 • Double - +5.0E-45 to +1.7E+308 • Object – Data of any type • String – 0 to 2000000000 Unicode characters
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Lab Exercise 3 • Exercise 3
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Loopings • Repetition of codes in a predefined counter or sequence
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For Loop For variable = starting point to ending point Next variable
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Example Dim ctr As Integer ctr = 0 For i = 1 To 10 ctr = ctr + 1 Next i VISUAL BASIC 6.0©
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While/ Wend • A repetition structure allows the programmer to specify that an action should be repeated depending on the value of the condition
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Syntax While condition Wend
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Code Dim ctr As Integer i=0 While i < 10 ctr = ctr + 1 i=i+1 Wend VISUAL BASIC 6.0©
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Do While Loop Do while Condition Loop
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Codes Dim ctr As Integer i=0 Do While i < 10 ctr = ctr + 1 i=i+1 Loop VISUAL BASIC 6.0©
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Array • Can store information and has indexes or memory address • Array have the same name and same type • The first element of an array is 0th Element • The position on the array is called index
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Syntax Dim array_name(size) as data type Store value on array Array_name(index) = value VISUAL BASIC 6.0©
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Example Dim arraysamp(3) As String arraysamp(0) = "a" arraysamp(1) = "b" arraysamp(2) = "c" VISUAL BASIC 6.0©
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List Box • ListBox – An area in which a list of items is displayed. The user can make a selection from the list by clicking on any item. Multiple elements can be selected.
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List Box Properties • List – Use to insert choices • Style – 1- Checkbox / 0 - Standard • Sorted – Sorts the value in ascending order (True/False)
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Methods • .additem = add a new choice on runtime – List1.AddItem "Item to add“
• .clear = removes all the items on the listbox – List1.Clear VISUAL BASIC 6.0©
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Methods • .RemoveItem – Removes a specific item – List1.RemoveItem (index)
• .ListCount – Number of items on the list – listBought.ListCount VISUAL BASIC 6.0©
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Laboratory Exercise 4 • CLICK ME
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Being Familiar with Ascii Codes • 128-character set of alphanumeric symbols • Number symbols which represent numeric codes on the computer
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Two types of key events • Keypress – fires when a key representing an ASCII character is pressed
– Does not determined the SHIFT, ALT and Control Key was pressed
• It is necessary to handle the second type of key events, use the Key up and the Key Down Events
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• KeyDown – Generated when key is initially pressed • KeyUp – Generated when key is released • KeyPress – Generated when key is pressed. Occurs repeatedly while key is held down
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KeyCode of Arrow key • Up Arrow – 38 • Down Arrow – 40 • Left Arrow – 37 • Right Arrow – 39 • Letter S - 83 VISUAL BASIC 6.0©
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Function • Defined procedures to meet the requirements needed • Can be called to do a specific task
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How to create functions Public Sub functionname() End Sub
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Code Public Sub msgboxhello() msgbox “HELLO!!!” End Sub
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Timer • Are non visible components that reside on a form, generating tick events at a set interval. • Interval are set in the timers interval • 1000 interval is equal to 1 Second
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Timer Properties and Events • Interval – number of seconds when a code is triggered • Timer – The only event of a timer
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Position of an Object in a Form • Left – X Axis • Top – Y Axis • Leftmost side value = 0 • Rightmost side value = 0 VISUAL BASIC 6.0©
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Laboratory Exercise 5 • Click Me
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Adding Extra Components 1. On the Menu bar click on Project > Components (CTRL + T) 2. On the controls tab check the checkbox of the object that you want to add on your program 3. Click on Apply then Close 4. Example (Microsoft Common Dialog Control 6.0)
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Common Dialog Box • Allows you to call the open or save dialog box.
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Common Dialog Properties • Filter – Show what type of file should be open • MaxFileSize – Show how big the maximum size of the file
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Methods • ShowOpen – Show the Open Dialog Box • ShowSave – Show the Save Dialog Box
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How to get the path • Cd.filename – save the whole path of the file • Cd.filetitle – save the file title of the file
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How t o add extra references • On the menu bar click project > references • Check the checkbox what command or references to add • Click OK VISUAL BASIC 6.0©
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Microsoft Scripting Runtime • Use to manipulate files and Directories
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File.Copyfile Dim file As New Scripting.FileSystemObject
File.copyfile source, destination,true/false
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How to create randomize number Randomize num = Int(Rnd * ctrRand) Where ctrRand = Range of random numbers
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How to declare global variable • Public variable as DataType
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How to add module • On the menu bar click Project > Add Module • Click Open
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How to add Extra Form • On the menu bar click Project > Add Form • Click Form then Open
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To open a form • Formname.show – Modal 1 = Disable the extra form – Modal 0 = Enable the extra form
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Unload or close a form • Unload Formname • Unload Me
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Laboratory Exercise 6 • Click Me
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Database Programming • References – used to load extra libraries
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How to add Active Data Objects 2.5 • On the menu bar click project > References • On the References dialog box find Microsoft ActiveX Data Objects 2.5 and check the check box • Click Ok VISUAL BASIC 6.0©
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How to Add modules • On the menu bar click Project > Add Modules • Click Open
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Declaring the ADODB.Connection • Public db As New ADODB.Connection
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Setting the ADODB Connection Public Sub dbConn() 'ACCESS CONNECTION STRING Set db = New ADODB.Connection db.CursorLocation = adUseClient db.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & App.Path & "\dbInformation.mdb;" & _ "Persist Security Info=False;" End Sub VISUAL BASIC 6.0©
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Declaring the ADODB.Recordset • Public rs As New ADODB.Recordset
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Setting the ADODB.Recordset Public Sub rsConn(table As String) Set rs = New ADODB.Recordset rs.CursorLocation = adUseClient rs.Open table, db, adOpenDynamic, adLockOptimistic End Sub
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Code for Add Records rs.AddNew rs(“Field Name") = source rs.Update
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Delete rs.Delete rs.Update
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Edit Records rs(“Field Name") = source rs.Update
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Search Record • rsConn “select * from Table where Field=‘” & txtBox & “’”
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Checking if there is no record • Rs.recordcount -check the number of records • Rs.eof – end of file • Rs.bof – Beginning of file
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Object Oriented Programming • uses "objects" and their interactions to design applications and computer programs • Programming techniques may include features such as encapsulation, modularity, polymorphism, and inheritance VISUAL BASIC 6.0©
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Encapsulation • principle of information hiding • the hiding of design decisions in a computer program that are most likely to change
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Modularity • software design technique which software is composed from separate parts, called modules
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Polymorphism • is the ability of objects belonging to different types to respond to method calls of the same name, each one according to an appropriate type-specific behavior. • controlling code can issue the same command to a series of objects and get appropriately different results from each one. VISUAL BASIC 6.0©
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Inheritance • is a way to form new classes (instances of which are called objects) using classes that have already been defined. • The new classes, known as derived classes, take over (or inherit) attributes and behavior of the pre-existing classes, which are referred to as base classes (or ancestor classes).
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Getting Started with VB6 • Menu bar – a special kind of control that lets the users select options and issue commands • Tool Bar – toolbar is a panel on which onscreen buttons, icons, menus or other input or output elements are placed
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• Toolbox - A collection of tools that act as storage area of controls you can place on your form. • Form window – a window you customize to create the user interface of your program
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• Project window – lists its components in a tree structured listing. Related objects appear together. • Properties window – a list of property of every control • Project – a collection of file that make up your application
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Getting Started 1. Open visual basic (Start > All programs > Microsoft Visual Studio > Microsoft Visual Basic 6.0 2. On the new project dialog box select standard exe to create a new program then click open VISUAL BASIC 6.0©
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Saving a Project 1. On the menu bar, click File > Save project. 2. Save every form and modules on your project in the same directory.
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Events • An activity that occurs during a program’s execution, such as a mouse click or a keystroke
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Most Use Events • Activate – executes when form is activated or in focus • Click – executes when a certain object is click by a mouse • Load – executes when a certain object is loaded or run for the first time VISUAL BASIC 6.0©
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• Unload - executes when a certain object is un loaded or terminated • Mouse Move – Executes when a mouse is move
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Form • Correspond with other controls • The main window of the program when run • Form Properties – – – –
Border Style Window State Caption Picture
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Changing properties during runtime Form1.BackColor = &H80FFFF Form1.Caption = “this change during runtime”
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Objects on Visual Basic • Label Box – control use to display text • Label Properties are: Alignment, Appearance, AutoSize, Fore Color, Caption
– Properties can be change on the properties window
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Code Label1.caption = “” ‘clears the text of a label Label1.caption = “This is a label” Label1.font = tahoma Label1.fontsize = 12 VISUAL BASIC 6.0©
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Command Button • is a widget that provides the user a simple way to trigger an event • Executes when triggered or clicked – – – –
Appearance Picture Style Caption
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Event • Click • DblClick
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Code • Command1.caption = “Save” • Command1.visible = false
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Text Box • Used to display information entered at design time or runtime. This is used to ask a user an input – – – – – – – –
Appearance BorderStyle Font Locked Maxlength Multiline ScrollBar Text
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Code • Text1.text = “” • Text1.locked = true • Text1.visible = true
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Visual Basic Operator • • • • • • •
^ - Exponent * - Multiplication / - Division + - Addition - - Subtraction Mod – Integer & - Concatenation
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Code • Text1.text = val(text1.text) + val(text2.text)
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Lab Exercise 1 • Create a simple payroll system which computes the basic salary of an employee – Example1
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Option Button • An object which allows the user to choose options or choices
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Properties of Option Box • Caption – Text displayed on option Button • Value – Can be True or False
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Combo Box • An object which allows the user to choose options or choices but in a drop down list
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Properties of a Combo Box • List – use to insert all the choices on your combo box • Text – the selected value or text • Style – type of a combo box (0Dropdown Combo, 1-Simple Combo, 2-Dropdown Combo) VISUAL BASIC 6.0©
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Methods • Actions can be triggered on an object • Example are: additem, clear ect.
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Adding Items on Combo on runtime Combo1.AddItem "Choice 1" Combo1.AddItem "Choice 2“ Clearing the items Combo1.clear VISUAL BASIC 6.0©
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Decision Making • If/then – Allows a program to make a decision based on the truth or falsity of some expression – It is a condition VISUAL BASIC 6.0©
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If then / else • Allows a user to make a decision but has two default decision
If then/ elseif /else • For two or more choices VISUAL BASIC 6.0©
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Logical Operators • • • • • • • •
> - Greater Than < - Less Than >= - Greater Than Equal <= - Less Than Equal <> - Not equal = - Equal And – Two Conditions that should be true Or – Two conditions that at least one condition can be true
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Code If Combo1.Text = "A" Then MsgBox "A" Else MsgBox "NOT A" End If VISUAL BASIC 6.0©
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Lab Exercise 2 • Click Here
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Date and Time • Date Function – Format(Date,”MMM DD, YYYY”)
• Time Function – Format(Time,”HH:MM:SS am/pm”)
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ImageBox • Insert image on your form • LoadPicture(“”) is use to load a picture on runtime
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Properties • Stretch
– True – Picture will adjust according to the size of your picture box – False – Picture will load on its normal size
• Picture
– Specify the picture or target picture
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Code • Image1.Picture = LoadPicture("C:\Documents and Settings\All Users\Documents\My Pictures\Sample Pictures\Sunset.jpg")
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Timer • Label1.Caption = Format(Time, "HH:MM:SS")
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MsgBox • Shows a pop up dialog box and informs the user • MsgBox "Prompt", button, "TitleBar"
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Sample Button • Vbinformation – Ok and Information Icon • VbYesNo – Yes and No Button • VbCritical – Critical Icon and Ok Button • Etc…
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Declaring a variable Dim – Dimension/use to declare a variable Dim lagyu As String
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Data Types • • • • • •
Boolean – true or false Char – One Unicode character Byte – 0 to 255 Date – Dates Decimal – 1.0E-28 to 7.9E+28 Short - -32,768 to 32,767
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• Integer - -2,147,483,648 to 2,147,483,647 • Long - -9,223,372,036,854,775,808 to 9,223,372,036,854,775,808 • Single - +1.5E-45 to +3.4E+38 • Double - +5.0E-45 to +1.7E+308 • Object – Data of any type • String – 0 to 2000000000 Unicode characters
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Lab Exercise 3 • Exercise 3
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Loopings • Repetition of codes in a predefined counter or sequence
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For Loop For variable = starting point to ending point Next variable
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Example Dim ctr As Integer ctr = 0 For i = 1 To 10 ctr = ctr + 1 Next i VISUAL BASIC 6.0©
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While/ Wend • A repetition structure allows the programmer to specify that an action should be repeated depending on the value of the condition
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Syntax While condition
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Code Dim ctr As Integer i=0 While i < 10 ctr = ctr + 1 i=i+1 Wend VISUAL BASIC 6.0©
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Do While Loop Do while Condition
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Codes Dim ctr As Integer i=0 Do While i < 10 ctr = ctr + 1 i=i+1 Loop VISUAL BASIC 6.0©
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Array • Can store information and has indexes or memory address • Array have the same name and same type • The first element of an array is 0th Element • The position on the array is called index
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Syntax Dim array_name(size) as data type Store value on array Array_name(index) = value VISUAL BASIC 6.0©
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Example Dim arraysamp(3) As String arraysamp(0) = "a" arraysamp(1) = "b" arraysamp(2) = "c" VISUAL BASIC 6.0©
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List Box • ListBox – An area in which a list of items is displayed. The user can make a selection from the list by clicking on any item. Multiple elements can be selected.
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List Box Properties • List – Use to insert choices • Style – 1- Checkbox / 0 - Standard • Sorted – Sorts the value in ascending order (True/False)
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Methods • .additem = add a new choice on runtime – List1.AddItem "Item to add“
• .clear = removes all the items on the listbox – List1.Clear VISUAL BASIC 6.0©
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Methods • .RemoveItem – Removes a specific item – List1.RemoveItem (index)
• .ListCount – Number of items on the list – listBought.ListCount VISUAL BASIC 6.0©
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Laboratory Exercise 4 • CLICK ME
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Being Familiar with Ascii Codes • 128-character set of alphanumeric symbols • Number symbols which represent numeric codes on the computer
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Two types of key events • Keypress – fires when a key representing an ASCII character is pressed
– Does not determined the SHIFT, ALT and Control Key was pressed
• It is necessary to handle the second type of key events, use the Key up and the Key Down Events
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• KeyDown – Generated when key is initially pressed • KeyUp – Generated when key is released • KeyPress – Generated when key is pressed. Occurs repeatedly while key is held down
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KeyCode of Arrow key • Up Arrow – 38 • Down Arrow – 40 • Left Arrow – 37 • Right Arrow – 39 • Letter S - 83 VISUAL BASIC 6.0©
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Function • Defined procedures to meet the requirements needed • Can be called to do a specific task
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How to create functions Public Sub functionname()
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Code Public Sub msgboxhello() msgbox “HELLO!!!” End Sub
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Timer • Are non visible components that reside on a form, generating tick events at a set interval. • Interval are set in the timers interval • 1000 interval is equal to 1 Second
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Timer Properties and Events • Interval – number of seconds when a code is triggered • Timer – The only event of a timer
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Position of an Object in a Form • Left – X Axis • Top – Y Axis • Leftmost side value = 0 • Rightmost side value = 0 VISUAL BASIC 6.0©
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Laboratory Exercise 5 • Click Me
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Adding Extra Components 1. On the Menu bar click on Project > Components (CTRL + T) 2. On the controls tab check the checkbox of the object that you want to add on your program 3. Click on Apply then Close 4. Example (Microsoft Common Dialog Control 6.0)
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Common Dialog Box • Allows you to call the open or save dialog box.
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Common Dialog Properties • Filter – Show what type of file should be open • MaxFileSize – Show how big the maximum size of the file
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Methods • ShowOpen – Show the Open Dialog Box • ShowSave – Show the Save Dialog Box
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How to get the path • Cd.filename – save the whole path of the file • Cd.filetitle – save the file title of the file
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How t o add extra references • On the menu bar click project > references • Check the checkbox what command or references to add • Click OK VISUAL BASIC 6.0©
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Microsoft Scripting Runtime • Use to manipulate files and Directories
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File.Copyfile Dim file As New Scripting.FileSystemObject
File.copyfile source, destination,true/false
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How to create randomize number Randomize num = Int(Rnd * ctrRand) Where ctrRand = Range of random numbers
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How to declare global variable • Public variable as DataType
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How to add module • On the menu bar click Project > Add Module • Click Open
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How to add Extra Form • On the menu bar click Project > Add Form • Click Form then Open
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To open a form • Formname.show – Modal 1 = Disable the extra form – Modal 0 = Enable the extra form
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Unload or close a form • Unload Formname • Unload Me
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Laboratory Exercise 6 • Click Me
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Database Programming • References – used to load extra libraries
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How to add Active Data Objects 2.5 • On the menu bar click project > References • On the References dialog box find Microsoft ActiveX Data Objects 2.5 and check the check box • Click Ok VISUAL BASIC 6.0©
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How to Add modules • On the menu bar click Project > Add Modules • Click Open
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Declaring the ADODB.Connection • Public db As New ADODB.Connection
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Setting the ADODB Connection Public Sub dbConn() 'ACCESS CONNECTION STRING Set db = New ADODB.Connection db.CursorLocation = adUseClient db.Open "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" & App.Path & "\dbInformation.mdb;" & _ "Persist Security Info=False;" End Sub VISUAL BASIC 6.0©
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Declaring the ADODB.Recordset • Public rs As New ADODB.Recordset
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Setting the ADODB.Recordset Public Sub rsConn(table As String) Set rs = New ADODB.Recordset rs.CursorLocation = adUseClient rs.Open table, db, adOpenDynamic, adLockOptimistic End Sub
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Code for Add Records rs.AddNew rs(“Field Name") = source rs.Update
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Delete rs.Delete rs.Update
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Edit Records rs(“Field Name") = source rs.Update
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Search Record • rsConn “select * from Table where Field=‘” & txtBox & “’”
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Checking if there is no record • Rs.recordcount -check the number of records • Rs.eof – end of file • Rs.bof – Beginning of file
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