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Switch
Function Switch is
related to the If/Then/Else structure.
Each argument passed to
Switch is either a condition or a value.
Any number of condition-value
pairs can be passed to Switch.
If a condition is True,
the value associated with that condition is returned.
If no condition is True,
Switch returns Null.
Function Switch does
not provide Else functionality; a value must be paired with a
condition. For example, the assignment
lblStudentGrade.Text = Microsoft.VisualBasic.Switch(grade >= 90, "A", _
grade >= 80, "B", _
grade >= 70, "C", _
grade >= 60, "D",
_
grade < 60, "F")
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IIf
Visual Basic provides the function IIf, which is closely related to
the If/Then/Else structure. Function IIf takes three arguments-the
condition, the value returned when the condition is True and the value returned
when the condition is False.
Example:
lblStatus.Text = IIf(grade >= 60, "Passed",
"Failed")
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Choose
Function Choose
is
related to the Select Case
statement.
-
The first argument is an
Integer
that specifies the index of any argument after the first argument.
-
Any number of items (of any type) can be provided after
the first argument.
-
Index values start at 1.
-
Example: Print
Choose(someVar,
"Red", "Green", "Blue")
-
prints either Red, Green or Blue depending on
the value of someVar.
-
If
someVar is 1, Red is
displayed.
-
If
someVar is 2, Green
is displayed.
-
If
someVar is 3, Blue
is displayed.
-
Choose returns
Null
if
someVar has a value that is not between 1 and 3
inclusive.
-
If a floating-point number is passed as the first
argument, it is rounded to the nearest Integer.
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