CS 106 Computing Fundamentals II Chapter 35

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CS 106Computing Fundamentals IIChapter
35Controls For Choices

• Herbert G. Mayer, PSU CS
• Status 7/17/2013
• Initial content copied verbatim from
• CS 106 material developed by
• CS professors Cynthia Brown Robert Martin

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Syllabus

• Controls For Choices
• Option Button
• Creating Option Buttons
• About the Demo
• Events

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Controls for Choices

• Lets look at new controls option buttons and
  check boxes
• These controls are designed to be used when you
  want the user of the program to have choices
• Well use conditionals to determine which values
  have been set and have the program act accordingly

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Option Buttons

• Option buttons come in groups, but only one
  button in the group can be selected
• We use the prefix opt for this control. Lets say
  there are three buttons in a group for choosing a
  size, Small, Medium, or Large
• We can name our buttons optSmall, optMedium, and
  optLarge

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Creating Option Buttons

• Generally start with a frame!! Then place Option
  Buttons into the frame such as
• Choose the Option Button tool in the Toolbox and
  create as many as you want in a group
• Name the buttons and change their text
• Notice that the buttons are round
• You are now ready to use them in a program

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Check Boxes

• Check boxes are similar to option buttons but
  more than one in a group can be checked
• While option buttons make sense for choosing
  something like model or color, check boxes can be
  used for choosing something like features, where
  more than one can be chosen (AC, disk brakes,
  super sound package, leather seats, fancy wheels,
  etc.)

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Creating Check Boxes

• Its the same procedure as for option buttons,
  but the frame is optional
• Yet if you pick a frame, create it first
• The logic of the associated conditional will be
  different since more than one can be checked
• Well use the prefix chk for these named control

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OptionDemo If statements, check boxes, option
buttons, demonstrated by showing HW3
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About the Demo

• Check if an option -or check box- Value is True
  to see if it is selected
• If chkTaller.Value Then
• btnPush.Height btnPush.Height 2
• End If
• sometimes programmers code
• If chkTaller.Value True Then
• btnPush.Height btnPush.Height 2
• End If

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Events

• Checking a box or selecting a button is an event.
  But if there is no code for an event, nothing
  happens
• There is no code for the event of selecting the
  red, blue, and green buttons. In HW3, their
  values are checked during the btnPush click event