CS0004: Introduction to
Programming
Select Case Statements and Selection Input
Review
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A condition is either…
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Relational Operators
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True or False
=
<>
<
>
<=
>=
Logical Operators
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And
Or
Not
Select Case Statements
Sometimes you want to check if a variable is one of many values. You can do this with If statements:
Dim a As Integer
If a = 1 Then
‘do something
ElseIf a = 2 Then
‘do something
ElseIf a = 3 Then
‘do something
Else
‘do something
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However, you can use select case statements, instead to form a more logical decision structure
Dim a As Integer
Select Case a
Case 1
‘do something
Case 2
‘do something
Case 3
‘do something
Case Else
‘do something
End Select
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Select Case Statements
General Form
Select Case selector
Case valueList1
action1
Case valueList2
action2
Case Else
actionOfLastResort
End Select
 The value lists can be literals, variables, expressions, or a range in the form
a To b where a and b are literals, variables, or expressions.
 Value lists can also be multiple values separated by a comma, for instance
you can have:
Case 1, 2, 5
 This case will be executed if the selector is either 1, 2 or 5
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Select Case Examples
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New Topics:
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Select Case Statements
Ranges
Selection Input
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Some controls in VB ask the user to make selections from
multiple choices. Some Examples are:
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Radio Buttons
Check Boxes
List Boxes
Radio buttons and check boxes can be grouped together
using group boxes.
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If controls are inside of a group box, it is said that the controls
are attached to the group box.
If multiple radio buttons are in the same group box, only one
of them can be selected at a time.
Radio Buttons
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Radio buttons are controls that when grouped, only one can
be checked (selected) at a time.
Radio buttons default event procedure is CheckedChanged
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This event happens when a radio button is either first checked or
unchecked.
Radio buttons have a property called Checked that holds the
boolean value of whether the box is checked or not.
radButton.Checked
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You can set whether a radio button is checked or not checked
with this property
radButton.Checked = True
radButton.Checked = False
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Select Case Statement with Radio Buttons
Example
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New Topics:
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Radio Buttons
CheckChanged Event Procedure
Checked Property
List Boxes
An input box is a list of strings in which each can be selected.
 We have added items to the list and cleared the list in previous
examples
lstTheList.Items.Add(parameter)
lstTheList.Items.Clear()
 You can also add items to the list box at design time in Visual Studio.
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Click the task button (the triangle) on the control in Visual Studio.
Click on “Edit Items” on the menu that appears
Add each item in a single line in the dialog box.
Click “OK”
You can access the item currently selected by using the Text
property of the list box.
The list box default event procedure is SelectedIndexChanged. This
means that the item that is selected has changed.
List Box Example
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New Topics:
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List Box
Design time list items
Check Boxes
Check boxes are like radio buttons, but multiple check
boxes can be checked at once.
 They also have a checked property
chkTheCheckBox.Checked
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The default event procedure for a check box is
CheckChanged
Check Box Example
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New Topics:
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Check Boxes
Font Property
Font Class
New Keyword