Lab Manual for V1

Lab Manual for VB

Activity 1 : Building User Interface

Intrinsic Controls

• Text Box

• Command Buttons

• Controls for making choices

• Special purpose control

Example: Poll system

The Code

Dim total, Excel_total, VG_total, G_total, Sat_total, Bad_total As Integer

Dim Excel_percent, VG_percent, G_percent, Sat_percent, Bad_percent As Single

Dim done As Boolean

Private Sub cmd_Vote_Click()

Picture1.Cls

If Option_Excel.Value = True Then

Excel_total = Excel_total + 1

Lbl_ExcelTotal = Excel_total

ElseIf Option_VG.Value = True Then

VG_total = VG_total + 1

Lbl_VGTotal = VG_total

ElseIf Option_G.Value = True Then

G_total = G_total + 1

Lbl_GTotal = G_total

ElseIf Option_Sat.Value = True Then

Sat_total = Sat_total + 1

Lbl_SatTotal = Sat_total

ElseIf Option_Bad.Value = True Then

Bad_total = Bad_total + 1

Lbl_BadTotal = Bad_total

End If

total = Excel_total + VG_total + G_total + Sat_total + Bad_total

Lbl_Total = total

Excel_percent = Excel_total / total

VG_percent = VG_total / total

G_percent = G_total / total

Sat_percent = Sat_total / total

Bad_percent = Bad_total / total

Lbl_Excel.Caption = Format(Excel_percent, "Percent")

Lbl_VG.Caption = Format(VG_percent, "Percent")

Lbl_G.Caption = Format(G_percent, "Percent")

Lbl_Sat.Caption = Format(Sat_percent, "Percent")

Lbl_Bad.Caption = Format(Bad_percent, "Percent")

Picture1.Line (100, 750)-(3800 * Excel_percent, 950), vbRed, BF

Picture1.Line (100, 1450)-(3800 * VG_percent, 1650), vbMagenta, BF

Picture1.Line (100, 2150)-(3800 * G_percent, 2350), vbGreen, BF

Picture1.Line (100, 2850)-(3800 * Sat_percent, 3050), vbBlue, BF

Picture1.Line (100, 3550)-(3800 * Bad_percent, 3750), vbYellow, BF

End Sub

Example : Pythagoras Theorem

The Code

Private Sub Command1_Click()

Dim AB, AC, BC As Single

AB = Val(Txt_AB.Text)

AC = Val(Txt_AC.Text)

BC = Val(Txt_BC.Text)

If AB <> 0 And AC <> 0 Then

BC = Sqr(AB ^ 2 + AC ^ 2)

Txt_BC.Text = Round(BC, 2)

ElseIf AB <> 0 And BC <> 0 Then

AC = Sqr(BC ^ 2 - AB ^ 2)

Txt_AC.Text = Round(AC, 2)

ElseIf AC <> 0 And BC <> 0 Then

AB = Sqr(BC ^ 2 - AC ^ 2)

Txt_AB.Text = Round(AB, 2)

End If

End Sub

Example : Digital Clock

In this program, you have to insert a timer control into the form . Then go to the properties window to set the timer's interval value to 1000 so that Visual Basic updates the time every 1000 milliseconds, or once a second. Other properties that you ought to set are to change the caption (here is My Clock) and to set Form1's MaxButton to false (so that it cannot be maximized by the user)

The Design Interface

The Run Time Interface

Now, double click the timer and enter the one line code as follows:

Private Sub Timer1_Timer()

Label1.Caption = Time

End Sub

Exercise 1

Develop a simple calculator using Intrinsic controls. Develop an application using Timer control and Image control. Image should move around the

form and when it hits the slide of the form its direction should be changed

Exercise 2

Design Course Details form with the following controls Combo box for course name Option button to display batch no Check box to display timings List Box for centre names

Exercise 3

Change the size of label by using HScroll Bar Change the speed of label by using HScrollBar

Activity 2 : Working with Menu and Dialog Boxes

Menu Editor Drop down menus Nested Menus Access key n short cut keys to menus Writing code for menu item Adding and deleting menu commands at Run Time. Popup Menus Context Menus

EXAMPLE 1:

The code

Private Sub mnuFileOpen_Click()

MsgBox "Code for 'Open' goes here.", vbInformation, "Menu Demo"

End Sub

Private Sub mnuFileSave_Click()

MsgBox "Code for 'Save' goes here.", vbInformation, "Menu Demo"

End Sub

Private Sub mnuFileSaveAs_Click()

MsgBox "Code for 'Save As' goes here.", vbInformation, "Menu Demo"

End Sub

Private Sub mnuFilePrint_Click()

MsgBox "Code for 'Print' goes here.", vbInformation, "Menu Demo"

End Sub

Private Sub mnuFileExit_Click()

Unload Me

End Sub

Private Sub mnuHelpAbout_Click()

MsgBox "Menu Demo" & vbCrLf _& "Copyright " & Chr$(169) & " 2004 thevbprogrammer.com", , _

"About"

End Sub

Exercise 1

Create Notepad with following menu options

Edit, Format and Exit

For exit option design confirmation Message Box Pop up menu for cut, copy and paste

Activity 3 : Programming Constructs

Variables and Constants Data Types: Built-in and UDT Arrays Operators Control Flow statements Unconditional Branch With statement

Example : Prime Number tester

In this program, I use the Select Case ......End Select statement to determine whether a number entered by a user is a prime number or not. For case 1, all numbers that are less than 2 are prime. In Case 2, if the number is 2, it is a prime number. In the last case, if the number N is more than 2, I need to divide this number by all the numbers from 3,4,5,6,........up to N-1, if it can be divided by any of these numbers, it is not a prime number, otherwise it is a prime number. I use a Do......Loop While statement to control the program flow. Here I also used a tag="Not Prime' to identify the number that is not prime, so that when the routine exits the loop, the label will display the correct answer.

Private Sub Command1_Click()Dim N, D As SingleDim tag As String

N = Val(TxtNumber.Text)

Select Case NCase Is < 2Lbl_Answer.Caption = "It is not a prime number"

Case Is = 2Lbl_Answer.Caption = "It is a prime number"

Case Is > 2D = 2DoIf N / D = Int(N / D) ThenLbl_Answer.Caption = "It is not a prime number"tag = "Not Prime"Exit DoEnd IfD = D + 1

Loop While D <= N - 1If tag <> "Not Prime" ThenLbl_Answer.Caption = "It is a prime number"End IfEnd SelectEnd Sub

Example: Quadratic Equation SolverQuadratic equation is a fairly straight forward high school mathematics problem. The quadratic equation solver was programmed to determine the number of roots the equation has as well as to compute the roots. It uses the determinant b2 -4ac to solve the problems. If b2 -4ac>0, then it has two roots and if b2 -4ac=0, then it has one root, else it has no root. To obtain the roots, the program uses the standard quadratic formula :

The Code

Private Sub Exit_Click()EndEnd Sub

Private Sub Form_Load()Dim a, b, c, det As IntegerDim root1, root2 As SingleDim numroot As IntegerEnd Sub

Private Sub new_Click()' To set all values to zeroCoeff_a.Text = ""Coeff_b.Text = ""Coeff_c.Text = ""Answers.Caption = ""

txt_root1.Visible = Falsetxt_root2.Visible = Falsetxt_root1.Text = ""txt_root2.Text = ""Lbl_and.Visible = FalseLbl_numroot.Caption = ""End Sub

Private Sub Solve_Click()a = Val(Coeff_a.Text)b = Val(Coeff_b.Text)c = Val(Coeff_c.Text)

'To compute the value of the determinant

det = (b ^ 2) - (4 * a * c)If det > 0 ThenLbl_numroot.Caption = 2root1 = (-b + Sqr(det)) / (2 * a)root2 = (-b - Sqr(det)) / (2 * a)Answers.Caption = "The roots are "Lbl_and.Visible = Truetxt_root1.Visible = Truetxt_root2.Visible = Truetxt_root1.Text = Round(root1, 4)txt_root2.Text = Round(root2, 4)

ElseIf det = 0 Thenroot1 = (-b) / 2 * aLbl_numroot.Caption = 1Answers.Caption = "The root is "txt_root1.Visible = Truetxt_root1.Text = root1Else

Lbl_numroot.Caption = 0Answers.Caption = "There is no root "

End If

End Sub

Exercise 1:

Design a Login Form allowing to enter User Name and password and command buttons ok , cancel and do the following:

Set the password Write a loop that continues until the password is right Display proper message if password is incorrect Clear the password text box and redisplay login form Password should be in “*” form Count the number of times the user types wrong password. When the user types right password, display a message box stating the number of

attempts made to get to the right password.

Exercise 2:

Design a user Interface which accepts Principal, annual Interest, term and Monthly Payment.

Form should be invoked when user presses ok from the log in screen of exercise 1.

There should be calculate button on this form which should calculate the monthly payment.

Exercise 3:

Write code to find Factorial of number entered by the user.

Activity 4: Working with Forms and Procedures

Form and its properties Multiple Forms Events MDI Procedures Functions Reusing procedures and Functions

Example : simple subroutine

Sub TestSub()

End Sub

After you enter the first line and press Enter, the second line will automatically be added for you. These lines represent the start and end of the subroutine. Any code inserted between these lines will be executed when the subroutine is called. A subroutine can be called in one of two ways: using the Call keyword, or by simply stating its name.

Sub TestSub()

MsgBox "Code in TestSub()"

End Sub

Private Sub Form_Load()

MsgBox "Code in Form_Load()"

TestSub

MsgBox "Back in Form_Load()"

End Sub

You can also use the Call keyword, as mentioned above:

Sub TestSub()

MsgBox "Code in TestSub()"

End Sub


MsgBox "Code in Form_Load()"

'This line is functionally equal as the line in the previous example

Call TestSub

MsgBox "Back in Form_Load()"

End Sub

Example: Function

Private Function Add(ByVal x As Integer, ByVal y As Integer) As Integer

Add = x + y

End Function


Dim a As Integer

Dim b As Integer

Dim c As Integer

a = 32

b = 64

c = Add(a, b)

MsgBox c

End Sub

Exercise 1

Create an application which should accept customer information from the customer like customer name, address, phone and email. The customer name and address cannot be left blank. Use GotFocus or LostFocus events to validate this. When the user closes the form, he will be prompted with a message box whether he really wants to quit the application. If he clicks ‘Yes’ then the application should end otherwise not.

Exercise 2

Create Multiple forms in project and call one from another. When another form is called the form that has lost focus should be hidden.

Exercise 3

Create a standard exe form and whenever the user releases the right mouse button a dialog box should be displayed.

Exercise 4

Create a standard module for accepting integer data only.

Exercise 5

Create MDI form with menus open, edit, format and exit. Also write the code for all the menus.

Activity 5: Control Array and Collection Control array Collections Form Collection Control Collection

Example: Mimic a Cell Phone Using Control Arrays

Private Sub ResetAll()

NumTimesClicked = 0

LastButtonClicked = -1

HasBeenDisplayed = False

End Sub


Buttons(2).Caption = "2" + vbCrLf + "ABC"

Buttons(3).Caption = "3" + vbCrLf + "DEF"

Buttons(4).Caption = "4" + vbCrLf + "GHI"

Buttons(5).Caption = "5" + vbCrLf + "JKL"

Buttons(6).Caption = "6" + vbCrLf + "MNO"

Buttons(7).Caption = "7" + vbCrLf + "PQRS"

Buttons(8).Caption = "8" + vbCrLf + "TUV"

Buttons(9).Caption = "9" + vbCrLf + "WXYZ"

End Sub

Private Sub Buttons_Click(Index As Integer)

' If a button without characters is clicked then exit out

If Index < 2 Or Index > 9 Then

ResetAll

Exit Sub

End If

If LastButtonClicked = Index Then

' We have been clicked before so keep track of it

If Index = 7 Or Index = 9 Then

' 7 & 9 have 4 characters so MOD 4

NumTimesClicked = (NumTimesClicked Mod 4) + 1

Else

' The rest of 3 characters so MOD 3

NumTimesClicked = (NumTimesClicked Mod 3) + 1

End If

Else

' We haven't clicked this button before so reset everything

LastButtonClicked = Index

NumTimesClicked = 1


End If

DisplayCurrentCharacter

End Sub

The sub DisplayCurrentCharacter is our largest chunk of code. What this routine does is read the value of our three global variables and display the correct character corresponding to which key was last pressed. Here is all the code:

Private Sub DisplayCurrentCharacter()

Dim curChar As String

Select Case LastButtonClicked

Case 2

Select Case NumTimesClicked

Case 1

curChar = "a"

Case 2

curChar = "b"

Case 3

curChar = "c"

End Select

Case 3


Case 1

curChar = "d"

Case 2

curChar = "e"

Case 3

curChar = "f"

End Select

Case 4


Case 1

curChar = "g"

Case 2

curChar = "h"

Case 3

curChar = "i"

End Select

Case 5


Case 1

curChar = "j"

Case 2

curChar = "k"

Case 3

curChar = "l"

End Select

Case 6


Case 1

curChar = "m"

Case 2

curChar = "n"

Case 3

curChar = "o"

End Select

Case 7


Case 1

curChar = "p"

Case 2

curChar = "q"

Case 3

curChar = "r"

Case 4

curChar = "s"

End Select

Case 8


Case 1

curChar = "t"

Case 2

curChar = "u"

Case 3

curChar = "v"

End Select

Case 9


Case 1

curChar = "w"

Case 2

curChar = "x"

Case 3

curChar = "y"

Case 4

curChar = "z"

End Select

End Select

If HasBeenDisplayed = True Then

' We have already displayed once so remove it and change it

Text1.Text = Left(Text1.Text, Len(Text1.Text) - 1)

End If

' Now add the current char to the display

Text1.Text = Text1.Text + curChar

Text1.SetFocus

Text1.SelStart = Len(Text1.Text) - 1

Text1.SelLength = 1

' Set the flag so we know we have displayed this character

HasBeenDisplayed = True

End Sub

Private Sub Timer1_Timer()

' This gets called if nothing has been pressed for 2 seconds

Text1.SelLength = 0

Text1.SelStart = Len(Text1.Text)

ResetAll

End Sub

Also add the following code to the current routine (bold lines are the new code)

Private Sub ResetAll()

NumTimesClicked = 0

LastButtonClicked = -1


Timer1.Enabled = False

End Sub

Private Sub DisplayCurrentCharacter()

Dim curChar As String

Timer1.Enabled = False

Select Case LastButtonClicked

Case 2


Case 1

curChar = "a"

Case 2

curChar = "b"

Case 3

curChar = "c"

End Select

Case 3


Case 1

curChar = "d"

Case 2

curChar = "e"

Case 3

curChar = "f"

End Select

Case 4


Case 1

curChar = "g"

Case 2

curChar = "h"

Case 3

curChar = "i"

End Select

Case 5


Case 1

curChar = "j"

Case 2

curChar = "k"

Case 3

curChar = "l"

End Select

Case 6


Case 1

curChar = "m"

Case 2

curChar = "n"

Case 3

curChar = "o"

End Select

Case 7


Case 1

curChar = "p"

Case 2

curChar = "q"

Case 3

curChar = "r"

Case 4

curChar = "s"

End Select

Case 8


Case 1

curChar = "t"

Case 2

curChar = "u"

Case 3

curChar = "v"

End Select

Case 9


Case 1

curChar = "w"

Case 2

curChar = "x"

Case 3

curChar = "y"

Case 4

curChar = "z"

End Select

End Select

If HasBeenDisplayed = True Then

' We have already displayed once so remove it and change it

Text1.Text = Left(Text1.Text, Len(Text1.Text) - 1)

End If

' Now add the current char to the display

Text1.Text = Text1.Text + curChar

Text1.SetFocus

Text1.SelStart = Len(Text1.Text) - 1

Text1.SelLength = 1

' Set the flag so we know we have displayed this character

HasBeenDisplayed = True

' Start the timer incase they don't click anyting for 2 seconds

Timer1.Enabled = True

End Sub

Exercise 1

Create a city catalog. Implement a collection for storing city names and temparatures.

Exercise 2

Write an application to display the name of all controls which are present on the form

Exercise 3

Write an application to add and remove command button at run time.

Activity 6 : Class Module

Building class module Property procedure Class builder

Exercise 1

Create a class called customer with properties like First name,Last name, Address, phone and email. Create methods for accepting details and displaying the details of the customer.

Exercise 2

Create a class supplier using the class builder. Add method fullname to concatenate first name and last name of the supplier.

Activity 7: Object Linking and Embedding

OLE container control Runtime embedding and linking OLE Automation

Saving, opening and Printing DocumentsExample: Printing in VB6 using the Printer Object

The application reads in a comma-delimited text file of customer records. Each record contains the following fields: last name, first name, address, city, state, and zip code. The determination for how these fields are to be laid out on the printed line is as follows: 19 characters for the first and last name combined, 1 space separator, 26 characters for the address, 1 space separator, 23 characters for the city, 1 space separator, 2 characters for the state, 2 space separator, 5 characters for the zip code. Main headings with date, time, and page number as well as column headings will appear at the top of each page. The user interface isn't much to speak of. There are two command buttons: "Print Customer List", which causes the above report to be printed, and an "Exit" button which ends the application.

The commented code for this application is shown below. A handful of techniques are introduced here which have not been covered in the previous tutorials, but will be in later tutorials.

Option Explicit'-----------------------------------------------------------------------------Private Sub cmdPrint_Click()

'-----------------------------------------------------------------------------Dim intLineCtr As Integer

Dim intPageCtr As Integer

Dim intX As Integer

Dim strCustFileName As String

Dim strBackSlash As String

Dim intCustFileNbr As Integer

Dim strFirstName As String

Dim strLastName As String

Dim strAddr As String

Dim strCity As String

Dim strState As String

Dim strZip As String

Const intLINE_START_POS As Integer = 6

Const intLINES_PER_PAGE As Integer = 60

' Have the user make sure his/her printer is ready ...

If MsgBox("Make sure your printer is on-line and " _

& "loaded with paper.", vbOKCancel, "Check Printer") = vbCancel _

Then

Exit Sub

End If

' Set the printer font to Courier, if available (otherwise, we would be relying on the default font for the Windows printer, which may or may not be set to an appropriate font) ...

For intX = 0 To Printer.FontCount - 1

If Printer.Fonts(intX) Like "Courier*" Then

Printer.FontName = Printer.Fonts(intX)

Exit For

End If

Next

Printer.FontSize = 10

' initialize report variables ...

intPageCtr = 0

intLineCtr = 99 ' initialize line counter to an arbitrarily high number

' to force the first page break

' prepare file name & number

strBackSlash = IIf(Right$(App.Path, 1) = "\", "", "\")

strCustFileName = App.Path & strBackSlash & "customer.txt"

intCustFileNbr = FreeFile

' open the input file

Open strCustFileName For Input As #intCustFileNbr

' read and print all the records in the input file

Do Until EOF(intCustFileNbr)

' read a record from the input file and store the fields there into VB variables

Input #intCustFileNbr, strLastName, strFirstName, strAddr, strCity, strState, strZip

' if the number of lines printed so far exceeds the maximum number of lines

' allowed on a page, invoke the PrintHeadings subroutine to do a page break

If intLineCtr > intLINES_PER_PAGE Then

GoSub PrintHeadings

End If

' print a line of data

Printer.Print Tab(intLINE_START_POS); _

strFirstName & " " & strLastName; _

Tab(21 + intLINE_START_POS); _

strAddr; _


strCity; _


strState; _


strZip

' increment the line count

intLineCtr = intLineCtr + 1

Loop

' close the input file

Close #intCustFileNbr

' Important! When done, the EndDoc method of the Printer object must be invoked.

' The EndDoc method terminates a print operation sent to the Printer object,

' releasing the document to the print device or spooler.

Printer.EndDoc

cmdExit.SetFocus

Exit Sub

' internal subroutine to print report headings

'------------

PrintHeadings:

'------------

' If we are about to print any page other than the first, invoke the NewPage

' method to perform a page break. The NewPage method advances to the next

' printer page and resets the print position to the upper-left corner of the

' new page.

If intPageCtr > 0 Then

Printer.NewPage

End If

' increment the page counter

intPageCtr = intPageCtr + 1

' Print 4 blank lines, which provides a for top margin. These four lines do NOT

' count toward the limit of 60 lines.

Printer.Print

Printer.Print

Printer.Print

Printer.Print

' Print the main headings


"Print Date: "; _

Format$(Date, "mm/dd/yy"); _

Tab(intLINE_START_POS + 31); _

"THE VBPROGRAMMER.COM"; _


"Page:"; _

Format$(intPageCtr, "@@@")


"Print Time: "; _

Format$(Time, "hh:nn:ss"); _


"CUSTOMER LIST"

Printer.Print

' Print the column headings


"CUSTOMER NAME"; _


"ADDRESS"; _


"CITY"; _


"ST"; _


"ZIP"


"-------------"; _


"-------"; _


"----"; _


"--"; _


"---"

Printer.Print

' reset the line counter to reflect the number of lines that have now

' been printed on the new page.

intLineCtr = 6

Return

End Sub

'-----------------------------------------------------------------------------

Private Sub cmdExit_Click()

'-----------------------------------------------------------------------------

End

End Sub

Exercise

In Excel create a sheet for recording the marks obtained by students in various subjects like Maths,physics,chemistry and Biology. In VB , create a form containing text boxes for student’s name Maths,physics, chemistry and biology and command buttons start,>>,<< and quit.

Using OLE automation display the data rows from Excel sheet. The start button establishes the OLE link with the desired Excel sheet and displays the

first data row from the sheet. The >> button skips to the next row and << skips to the previous row When skipping the rows ensure that you do not go beyond the range of the data rows

available in your sheet. The Quit button should terminate the link and end the application.

Activity 8: Ms Windows common and Third party controls

ImageList control ListView control TreeView control TabStrip control Controls for accepting User Input

ImageCombo control UpDown control MonthView control DTPicker control

StatusBar control ProgressBar control Slider Control Animation Control Common Dialog control

Color dialog

Font dialog Open, SaveAs dialog Print dialog Help dialog

RichTextBox control LoadFile method SaveFile method

Example: COMMON DIALOG DEMO PROGRAM

The Common Dialog demo program shows how to use each of the six types of dialog boxes. The design-time form is shown below, with the names and property settings for each control on the form, as well as for the form itself, shown in callouts.

Option Explicit

Private mstrLastDir As StringPrivate Sub Form_Load()

mstrLastDir = App.Path

End SubPrivate Sub cmdOpen_Click()

Dim strBuffer As String

Dim intDemoFileNbr As Integer

Dim strFileToOpen As String

On Error GoTo cmdOpen_Click_Exit

With dlgDemo

.CancelError = True

.InitDir = mstrLastDir

.Flags = cdlOFNHideReadOnly

.FileName = ""

.Filter = "Text Files(*.txt)|*.txt|All Files(*.*)|*.*"

.ShowOpen

strFileToOpen = .FileName

End With

On Error GoTo cmdOpen_Click_Error

intDemoFileNbr = FreeFile

Open strFileToOpen For Binary Access Read As #intDemoFileNbr

strBuffer = Input(LOF(intDemoFileNbr), intDemoFileNbr)

txtTestFile.Text = strBuffer

Close #intDemoFileNbr

mstrLastDir = Left$(strFileToOpen, InStrRev(strFileToOpen, "\") - 1)

Exit Sub

cmdOpen_Click_Error:

MsgBox "The following error has occurred:" & vbNewLine _

& "Err # " & Err.Number & " - " & Err.Description, _

vbCritical, _

"Open Error"

cmdOpen_Click_Exit:

End SubPrivate Sub cmdSave_Click()

Dim strBuffer As String

Dim intDemoFileNbr As Integer

Dim strFileToSave As String

On Error GoTo cmdSave_Click_Exit

With dlgDemo

.CancelError = True

.InitDir = mstrLastDir

.Flags = cdlOFNOverwritePrompt + cdlOFNPathMustExist

.FileName = ""

.Filter = "Text Files(*.txt)|*.txt|All Files(*.*)|*.*"

.ShowSave

strFileToSave = .FileName

End With

On Error GoTo cmdSave_Click_Error

intDemoFileNbr = FreeFile

Open strFileToSave For Binary Access Write As #intDemoFileNbr

strBuffer = txtTestFile.Text

Put #intDemoFileNbr, , strBuffer

Close #intDemoFileNbr

mstrLastDir = Left$(strFileToSave, InStrRev(strFileToSave, "\") - 1)

Exit Sub

cmdSave_Click_Error:



vbCritical, _

"Save Error"

cmdSave_Click_Exit:

End Sub

Private Sub cmdPrint_Click()

Dim intX As Integer

Dim intCopies As Integer

On Error GoTo cmdPrint_Click_Exit

With dlgDemo

.CancelError = True

.Flags = cdlPDHidePrintToFile + cdlPDNoPageNums _

+ cdlPDNoSelection

.ShowPrinter

intCopies = .Copies

End With

On Error GoTo cmdPrint_Click_Error

For intX = 0 To Printer.FontCount - 1

If Printer.Fonts(intX) Like "Courier*" Then

Printer.FontName = Printer.Fonts(intX)

Exit For

End If

Next

Printer.FontSize = 10

For intX = 1 To intCopies

If intX > 1 Then

Printer.NewPage

End If

Printer.Print txtTestFile.Text

Next

Printer.EndDoc

Exit Sub

cmdPrint_Click_Error:



vbCritical, _

"Print Error"

cmdPrint_Click_Exit:

End Sub

Private Sub cmdColor_Click()

Dim lngColor As Long

On Error GoTo cmdColor_Click_Exit

With dlgDemo

.CancelError = True

.ShowColor

lngColor = .Color

End With

On Error GoTo cmdColor_Click_Error

lblColor.BackColor = lngColor

Exit Sub

cmdColor_Click_Error:



vbCritical, _

"Color Error"

cmdColor_Click_Exit:

End Sub

Private Sub cmdFont_Click()

Dim lngFont As Long

On Error GoTo cmdFont_Click_Exit

With dlgDemo

.CancelError = True

.Flags = cdlCFBoth + cdlCFForceFontExist + cdlCFEffects

.ShowFont

On Error GoTo cmdFont_Click_Error

lblFont.FontBold = .FontBold

lblFont.FontItalic = .FontItalic

lblFont.FontName = .FontName

lblFont.FontSize = .FontSize

lblFont.FontStrikethru = .FontStrikethru

lblFont.FontUnderline = .FontUnderline

lblFont.ForeColor = .Color

lblFont.Caption = .FontName & ", " & .FontSize & " pt"

End With

Exit Sub

cmdFont_Click_Error:



vbCritical, _

"Font Error"

cmdFont_Click_Exit:

End SubPrivate Sub cmdHelp_Click()

On Error GoTo cmdHelp_Click_Error

With dlgDemo

.CancelError = True

.HelpCommand = cdlHelpForceFile

.HelpFile = App.Path & "\JETSQL35.HLP"

.ShowHelp

End With

Exit Sub

cmdHelp_Click_Error:

End Sub

Example 2: Let’s create a program that enables the users to open and choose files from the folders in their PC. This can be done easily using a picture box and a common dialog box. In this program, you need to insert a picture box, a common dialog box and an image. In the image properties windows, click on the picture property and select a picture that resembles an open file icon. The procedure to open the common dialog box to browse the picture files as well as to load the selected picture into the picture box is :-

CommonDialog1.Filter = "Bitmaps(*.BMP)|*.BMP|Metafiles(*.WMF)|*.WMF|Jpeg Files(*.jpg)|*.jpg|GIF Files(*.gif)|*.gif|Icon Files(*.ico)|*.ico|All Files(*.*)|*.*"

CommonDialog1.ShowOpen

Picture1.Picture = LoadPicture(CommonDialog1.FileName)

The filter property of the common dialog box uses the format as shown below

Bitmaps(*.BMP)|*.BMP

to specify the file type, and uses the pipe line | to separate different file types.Visual Basic supports most of the picture formats namely bmp, wmf, jpg, gif, ico(icon) and

cur(cursor) files. The command CommonDialog1.ShowOpen

is to open the common dialog box and the command

Picture1.Picture = LoadPicture (CommonDialog1.FileName)

is to load the selected picture file into the picture box.

The whole program is shown below and the output is shown in the figure below:

Private Sub Image1_Click()

CommonDialog1.Filter = "Bitmaps(*.BMP)|*.BMP|Metafiles(*.WMF)|*.WMF|Jpeg Files(*.jpg)|*.jpg|GIF Files(*.gif)|*.gif|Icon Files(*.ico)|*.ico|All Files(*.*)|*.*"

CommonDialog1.ShowOpen

Picture1.Picture = LoadPicture (CommonDialog1.FileName)

End Sub

Exercise 1 Create a small application which consists of a slider control and a text control. As the slider

moves towards the right, the text box control should grow in size. When the slider is moved towards left, the size of text box control should decrease.

Exercise 2

Create a small application which has a ImageCombo box control which stores any of three font types of the label control. When the user selects the specific font from ImageCombo box, the font of the caption of label control should change accordingly. Also add an UpDown control which is used for incrementing ar decrementing the font size.

Exercise 3

Save and load files using Common Dialog box

Exercise 4

A training Institute runs two types of the courses (a) Short term (b) Long term courses. Each type of course can then again have students which do courses in (a) Fast track (b) Slow track and (c) Superfast track.

Create a small application which uses a TabStrip control and TreeView control such that the TabStrip control enables to switch between two courses Short Term and Long Term. The TreeView Control should help in viewing the list of students in each of three tracks.

Activity 9: Managing database Access Using data Control

Database Access using Visual Basic Designing a database Data Control and Data Bound Control Data Control events Creating database file using Visual Data Manager Creating Form using Data Form wizard Data Access objects DataBondGrid Control DataBound List and Combo Box control

Example 1: Connecting to an Access Database Using the VB Data Control

STEPS:

1. Open a new Visual Basic project.

2. Put a data control (an intrinsic control, located in the VB toolbox) on the form and set the properties .

Notes: When you use the Data Control in a project, the properties that must be set are DatabaseName and RecordSource, in that order. DatabaseName is the name of the database you want to use, and the RecordSource is the name of the table in that database that you want to use.

3. On your form, create a text box for each field in the Authors table, with labels. (If you were to open the database in Access, you would see that the three fields of the Authors table are Au_ID, Author, and Year Born.) Set the properties of the three textboxes as follows:

Name DataSource DataField

txtAuthID datAuthors Au_ID

txtAuthor datAuthors Author

txtYearBorn datAuthors Year Born

In addition, set the Enabled property of txtAuthID to False.

When you want a control (such as a text box) to display data from a database, the properties that must be set are DataSource and Datafield. The DataSource is the name of the data control on the form (it should already be configured), and the DataField is the name of the particular field in the database that should be displayed in the control (this field will be in the table that was chosen for the RecordSource of the data control).

At this point, your form should resemble the screen-shot below:

4. Save and run the project. Use the arrows on the data control to scroll through the data.

5. On any record, change the data in the author name or year born field. Move ahead, then move back to the record you changed. Note that your changes remain in effect. The data control automatically updates a record when you move off of the record.

Example 2: Using Navigation Buttons with a Data Control

In the previous exercise, you saw that by clicking specific buttons of the data control, you could move to the first, previous, next, or last record. What is happening is that the data control is automatically invoking specific methods of the recordset object: namely the MoveFirst, MovePrevious, MoveNext, and MoveLast methods. You can also invoke these methods through code, which is what this exercise demonstrates.

STEPS:

1. Copy the files from Exercise #1 into a new folder and open the VBP file in the new folder.

2. Set the Visible property of the data control (datAuthors) to False.

3. Make four command buttons with the following properties:

Name Caption

cmdMoveNext Next Record

cmdMoveLast Last Record

cmdMovePrevious Previous Record

cmdMoveFirst First Record

At this point, your form should resemble the screen-shot below

4. Put the following four lines of code in the appropriate Click events for the buttons:

Event Code

cmdMoveNext_Click datAuthors.Recordset.MoveNext

cmdMoveLast_Click datAuthors.Recordset.MoveLast

cmdMovePrevious_Click datAuthors.Recordset.MovePrevious

cmdMoveFirst_Click datAuthors.Recordset.MoveFirst

5. Save and run your program.

6. Move to the last record and then click the Move Next button twice. What happens? (Fix this)

Exercise 1 Access Customers table from NorthWind database. Design and develop an application

which will access all the fields of the customers table and show each record at a time on the form using bound controls. The Form will only access the database using a data control and eleven text box controls. The form should be used to browse the customer data.

Exercise 2

Using Data Form Wizard create the same application as given in Exercise 1. Add more functionalities to the application such that you are able to add and update the records.

Exercise 3

Create a table called item using Visual data manager. The table should have the following fields like Item No, Name, Price, Quantity.

Develop an application which accesses the Item table. In this application you will not use data control to access the database, instead of that use Data Access object. The form will have First, Last, Previous, Next, New, Update, Delete and save command buttons .

In this application when the form is loaded, the save button should be disabled. The Update button should update the table with the contents displayed on the form. Following Validity checks must be done before updating and saving data.

No field should be left blank and the item no should accept only numeric values. The delete button should delete the current record displayed on the form. When

Delete button is clicked ask user for confirmation. When New button is clicked, fields should be blanked out and Save button should get

enabled and caption of close button should be changed to cancel and accordingly the

function of the button should also change. After the user has entered a record, the save button should be clicked for the record to be actually added to the table and also the caption of cancel button should again change to close.

On clicking the Next button when the user is on the last record, an appropriate message should be displayed. Similarly, display the message when the previous button is pressed when user is on first record.

Activity 10: Data Project and Report Handling

Data Project Data Report Crystal Reports

Exercise

Make Reports depending upon your project requirements.

Lab Manual for V1

Documents

Transcript of Lab Manual for V1