Chapter 11 Additional Controls and Ojects Outline and Objectives

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Chapter 11 Additional Controls and OjectsOutline
and Objectives

• List Boxes and Combo Boxes
• The List Box Control
• The Combo Box Control
• Nine Elementary Controls
• Frame, Check Box, Option Button, Horizontal
  Scroll Bar, Vertical Scroll Bar, Timer, Shape,
  Line, Image
• Five Additional Objects

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11.1 The List Box Control
Example 1 Private Sub cmdAdd_Click() Dim item
As String item InputBox("Item to Add")
lstOxys.AddItem item End Sub Private Sub
Form_Load() lstOxys.AddItem "jumbo shrimp"
lstOxys.AddItem "definite maybe"
lstOxys.AddItem "old news" lstOxys.AddItem
"good grief" End Sub

• Provides a list of items to the user
• The items on the list can either be specified at
  design time or set with code in the Form-Load
  event procedure
• Items can be accessed, added, deleted from the
  list by code
• Use prefix lst for naming a List Box

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Useful Properties and Methods of List Box

• If Sorted property is set to true, the items will
  automatically be displayed in alphabetic order.
• AddItem method adds a string to the list.
• RemoveItem n statement deletes the item of index
  n from the list.
• ListCount property returns the number of items in
  the list
• Each item in the list is identified by an index
  number, and ListIndex property is the index of
  the item currently highlighted in list box.

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Adding and deleting items from the list Box

• Private Sub lstOxys_Click()
• picSelected.Cls
• picSelected.Print "The selected item is"
• picSelected.Print Chr(34) lstOxys.Text
  Chr(34) "."
• End Sub
• Private Sub cmdAdd_Click()
• Dim item As String
• item InputBox("Item to Add")
• lstOxys.AddItem item
• End Sub
• Private Sub LstOxys_DblClick()
• lstOxys.RemoveItem lstOxys.ListIndex
• End Sub

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Example 2, pp. 519uses NewIndex and ItemData to
provide data from a file
In the General Declaration Section Dim
inventor(0 To 10) as string Dim yr(0 To 10) as
integer

• Private Sub Form_Load()
• Dim what As String, who As String, when As
  Integer, index As Integer
• Open App.Path "\INVENTOR.TXT" For Input As 1
• index 0
• Do While (index lt UBound(inventor)) And (Not
  EOF(1))
• Input 1, what, who, when
• index index 1
• lstInvents.AddItem what
• lstInvents.ItemData(lstInvents.NewIndex)
  index
• inventor(index) who
• yr(index) when
• Loop
• Close 1
• End Sub

Add the item to the list and record the index for
each record
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Example Continued

• Private Sub lstInvents_Click()
• lblWho.Caption inventor(lstInvents.ItemData(ls
  tInvents.ListIndex))
• lblWhen.Caption Str(yr(lstInvents.ItemData(lst
  Invents.ListIndex)))
• End Sub

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The Combo Box Control

• A combo box is best thought of as a text box with
  a help list attached.
• The user has the option of either typing in
  information or just selecting the appropriate
  information from a list.
• Two most useful types of combo box are
• Dropdown combo box
• Simple combo box
• Use prefix cbo for naming a combo box

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Style of Combo Boxes
Dropdown Combo Box
Simple Combo Box
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Example 3, pp. 521

• Private Sub cmdDisplay_Click()
• txtDisplay.Text cboTitle.Text " "
  txtName.Text
• End Sub

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Drive, Directory, and File List Box Controls

• There are three file-related controls
• DriveListBox, DirListBox, FileListBox
• VB does much of the work of providing appropriate
  lists for the three boxes.
• Windows determines the contents of the drive box.
• The programmer determines the contents of
  directory list boxes and file list boxes with
  Path properties.
• Use prefixes drv, dir, and fil for the names of
  the drive, directory, and file list box controls
  respectively.

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Example 4display the full name of any file on
any drive

• Private Sub cmdDisplay_Click()
• picFileSpec.Cls
• picFileSpec.Print dirList.Path
• If Right(dirList.Path, 1) ltgt "\" Then
• picFileSpec.Print "\"
• End If
• picFileSpec.Print filList.FileName
• End Sub
• Private Sub dirList_Change()
• filList.Path dirList.Path
• End Sub
• Private Sub drvList_Change()
• dirList.Path drvList.Drive
• End Sub

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11.2 Nine Elementary Controls

• Frame
• Check Box
• Option Button
• Horizontal Scroll Bar
• Vertical Scroll Bar
• Timer
• Shape
• Image

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The Frame Control

• Used to group related set of controls
• Is a passive object
• Useful when working with group of controls

Frame
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The Check Box Control

• Provides a yes/no option to the user
• The value property of check box is 0 when the
  check box is not checked and 1 if the check box
  is checked
• At run time, the user triggers the Click event by
  checking and unchecking the box
• Use prefix chk for naming a Check box

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Example of Using Check Box

• Private Sub Tally()
• Dim sum As Single
• If chkDrugs.Value 1 Then
• sum sum 12.51
• End If
• If chkMedical.Value 1 Then
• sum sum 25.25
• End If
• lblAmount.Caption FormatCurrency(sum)
• End Sub

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The Option Button Control

• Used to give the user a single choice from
  several options.
• Only one option button in a group can be on at
  the same time.
• The value property of an option button tells if
  the button is on or off.
• Use prefix opt for naming option buttons

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Example of Option Button Control

• Private Sub cmdStatus_Click()
• picStatus.Cls
• If optOpt1.Value True Then
• picStatus.Print "Option1 is on.
• End If
• If optOpt2.Value True Then
• picStatus.Print "Option2 is on."
• End If
• End Sub
• Private Sub Form_Load()
• optOpt1 False 'Turn off optOpt1
• optOpt2 False 'Turn off optOpt2
• End Sub

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Another Example of Option Button Control

• Private Sub opt12pt_Click()
• txtInfo.Font.Size 12
• End Sub
• Private Sub opt18pt_Click()
• txtInfo.Font.Size 18
• End Sub
• Private Sub opt24pt_Click()
• txtInfo.Font.Size 24
• End Sub

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The Horizontal and Vertical Scroll Bar Controls

• The main properties of a scroll bar are Min, Max,
  Value, SmallChange, and LargeChange, which are
  set to integers.
• Use prefix hsb for naming horizontal scroll bar
• Use prefix vsb for naming Vertical scroll bar

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Example 5, pp. 534uses scroll bars to move a
smiling face around the form

• Private Sub hsbXPos_Change()
• lblFace.Left hsbXPos.Value
• End Sub
• Private Sub hsbXPos_Scroll()
• lblFace.Left hsbXPos.Value
• End Sub
• Private Sub vsbYPos_Change()
• lblFace.Top vsbYPos.Value
• End Sub
• Private Sub vsbYPos_Scroll()
• Let lblFace.Top vsbYPos.Value
• End Sub

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The Timer Control

• The timer control, is invisible during run time.
• It triggers an event after a specified amount of
  time.
• The length of time is measured in milliseconds
• The event triggered each time Timer1.Interval
  milliseconds elapses is called Timer1.Timer().
• To begin a timer, set its Enabled property to
  True.
• To stop a timer, set its Enabled property to
  False or set its Interval to 0.
• Use prefix tmr for naming Timer control

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Example 6create a stopwatch that updates the
time every tenth of a second

• Private Sub cmdStart_Click()
• lblTime.Caption " 0" 'Reset watch
• tmrWatch.Enabled True
• End Sub
• Private Sub cmdStop_Click()
• tmrWatch.Enabled False
• End Sub
• Private Sub tmrWatch_Timer()
• lblTime.Caption Str(Val(lblTime.Caption)
  0.1)
• End Sub

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The Shape Control

• The shape control assumes one of six possible
  predefined shapes depending on the value of its
  shape property.
• Most useful properties are BackStyle,
  BorderWidth, BorderStyle, BackColor, FillStyle,
  FillColor, and Visible.
• Use prefix shp for naming shape controls

Effect achieved with Shape control
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The Line Control

• The Line control, produces lines of various
  thickness, styles, and colors to enhance the
  visual appearance of the forms.
• Most useful properties are BorderColor,
  BorderWidth, BorderStyle, and Visible.
• Use prefix lin for naming Line controls

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The Image Control

• It holds pictures stored in graphics files.
• Pictures are placed in image controls with the
  Picture property.
• If the Stretch property is set to True, the
  pictures will be resized to fit the image
  control.
• A picture can be assigned to an image control at
  run time by using the LoadPicture function.
• Use prefix img for naming Image controls

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11.3 Five Additional Objects

• Microsoft FlexGrid Control
• Menu Control
• Common Dialog Control
• Clipboard
• Multiple Forms

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The Microsoft FlexGrid Control

• A grid is a rectangle arrray used to display
  tables or to create spreadsheet-like application,
• To add the grid control, click on Components in
  the project menu, click on the Controls tab, and
  check the Microsoft FlexGrid Control 6.0. Then
  press OK button.
• Use prefix msg for naming FlexGrid controls

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The Microsoft FlexGrid Control

• The number of rows or columns can be specified at
  design time with Rows and Column properties or at
  run time
• The width of each column can be specified only at
  run time with the ColWidth property.
• The individual rectangles are called cells.
• At any time, one cell is singled out as the
  current cell.
• The statement msgFlex.Text str places the value
  of the str in the current cell

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The Menu Control

• VB forms can have menu bars with sub menus and
  dropdown menus at different levels.
• Each menu item is treated as a distinct control
  that responds to only one event - the click
  event.
• Menus are created with the Menu Editor window
  available from the Tools menu.
• Use prefix mnu for naming Menu controls

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Example 3, pp. 551 a menu is used to alter the
appearance of the contents of a text box

• Private Sub mnu12_Click()
• txtInfo.Font.Size 12
• End Sub
• Private Sub mnu24_Click()
• txtInfo.Font.Size 24
• End Sub
• Private Sub mnuCourier_Click()
• txtInfo.Font.Name "Courier"
• End Sub
• Private Sub mnuTimesRm_Click()
• txtInfo.Font.Name "Times New Roman"
• End Sub

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The Clipboard Object

• The clipboard object is used to copy or move text
  from one location to another.
• It can be used to transfer information from one
  Windows application to another.
• If str is a string, then the statement
  Clipboard.SetText str replaces any text currently
  in the clipboard with str.
• The statement strClipboard,GetText() assigns the
  text currently to the string variable str.

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Multiple Forms

• A VB program can contain more than one form.
• Additional forms are created from the Project
  menu with Add Form.
• The name of each form appears in the Project
  Explorer window.
• Forms are hidden or activated with statement such
  as Form1.Hide or Form2.Show.
• Each form has its own controls and code.

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Example 4, pp. 553uses a second form as a dialog
box to total the different source of income

• Private Sub cmdShowTot_Click()
• frmSources.Show vbModal
• End Sub
• Private Sub cmdCompute_Click()
• Dim sum As Single
• sum Val(txtWages.Text) Val(txtInterest.Text)
  Val(txtDividend.Text)
• frmIncome.txtTotal.Text FormatCurrency(Str(sum
  ))
• frmSources.Hide
• End Sub

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Multiple Forms

• You can declare global variables and procedures
  that are available to all forms.
• To do so, select Add Module from the Project menu
  and then double-click on the Module icon.
• Procedures created in this code window with the
  Public keyword will be available to all forms.
• To declare a variable that is available to all
  forms, declare it in Module1 window, but use the
  keyword Public instead of Dim.
• Save the code module by choosing Save Module As
  from the File menu.

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The Common Dialog Control

• To add a Common Dialog control, select Components
  from the Project menu, click the Controls tab,
  and click on the check box for Microsoft Common
  Dialog Control 6.0. Then press OK button.
• Use prefix dlg for naming Common Dialog controls.
• The Common Dialog control has no events, only
  methods and properties.
• It is also invisible. To produce a common dialog
  box, you execute a statement such as dlg.ShowFont

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The Common Dialog Control

• The different types of dialog boxes

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Examplea program to select the color and the
font for the text box using dialog boxes

• Private Sub cmdColor_Click()
• dlgStyle.Flags 3
• dlgStyle.Action 3
• txtInfo.ForeColor dlgStyle.Color
• End Sub
• Private Sub cmdFont_Click()
• dlgStyle.Flags 3
• dlgStyle.ShowFont
• txtInfo.Font.Name dlgStyle.FontName
• txtInfo.Font.Bold dlgStyle.FontBold
• txtInfo.Font.Italic dlgStyle.FontItalic
• txtInfo.Font.Size dlgStyle.FontSize
• End Sub

Select the Color common dialog box
Select the Font common dialog box