Name
Switch Function
Class
Microsoft.VisualBasic.Interaction
Syntax
Switch(expr-1, value-1[, expr-2, value-2 ... [, _
expr-n,value-n]]
)
-
expr
Use: Required
Data Type: Object
A number of expressions to be evaluated
-
value
Use: Required
Data Type: Object
An expression or value to return if the associated expression evaluates to
True
Return Value
An Object value or expression
Description
Evaluates a list of expressions and, on finding the first expression
to evaluate to True
, returns an associated value
or expression
Rules at a Glance
A minimum of two expression/value pairs is required; additional pairs are optional.
Expressions are evaluated from left to right.
If none of the expressions is
True
, theSwitch
function returnsNothing
.If multiple expressions are
True
,Switch
returns the value that corresponds to the firstTrue
expression.value
can be a constant, variable, or expression.
Example
The GetTextColor
function uses the
Switch
function to return an RGB color value
that depends on the sign of the integer passed to it as a parameter.
To access the Color structure, it imports the System.Drawing
namespace of the Base Class Library.
Private Function GetTextColor(lValue As Integer) As Integer Dim fColor As New Color Dim iColor As Integer fColor = Switch(lValue > 0, Color.Blue, _ lValue = 0, Color.Black, _ lValue < 0, Color.Red) ' Convert color name to RGB color and strip out ' high order byte of high-order word iColor = fColor.ToArgb and &H00FFFFFF GetTextColor = iColor End Function
Programming ...
Get VB .NET Language in a Nutshell now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.