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Update If Then Else (Visual Basic) to improve CSAT (#4942)
* Added Quick links to example code section * Revised based on review feedback * Updating code samples * Revising links * Updating Code sample links based on feedback * revising code sample links * Updating highlighting * Updated code comments, changed header case * Added Output at end of each sample, updated highlighting
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‎docs/visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_1.vb‎

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Dim count As Integer = 0
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Module Multiline
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Public Sub Main()
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'Create a Random object to seed our starting value
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Dim randomizer As New Random()
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'set our variable
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Dim count As Integer = randomizer.Next(0, 5)
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Dim message As String
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'If count is zero, output will be no items
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If count = 0 Then
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message = "There are no items."
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'If count is 1, output will be "There is 1 item.".
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ElseIf count = 1 Then
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message = "There is 1 item."
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'If count is greater than 1, output will be "There are {count} items.", where {count} is replaced by the value of count.
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Else
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message = "There are " & count & " items."
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message = $"There are {count} items."
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End If
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Console.WriteLine(message)
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End Sub
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End Module
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'This example displays output like the following:
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' There are 4 items.

‎docs/visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_2.vb‎

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Module Nested
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Public Sub Main()
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' Run the function as part of the WriteLine output.
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Console.WriteLine("Time Check is " & CheckIfTime() & ".")
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End Sub
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Private Function CheckIfTime() As Boolean
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' Determine the current day of week and hour of day.
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Dim dayW As DayOfWeek = DateTime.Now.DayOfWeek
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Dim hour As Integer = DateTime.Now.Hour
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' Return True if Wednesday from 2 to 4 P.M.,
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' or if Thursday from noon to 1 P.M.
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' Return True if Wednesday from 2 to 3:59 P.M.,
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' or if Thursday from noon to 12:59 P.M.
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If dayW = DayOfWeek.Wednesday Then
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If hour = 14 Or hour = 15 Then
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Return True
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Else
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Return False
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End If
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End Function
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End Function
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End Module
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'This example displays output like the following:
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'Time Check is False.

‎docs/visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_3.vb‎

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Module SingleLine
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Public Sub Main()
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'Create a Random object to seed our starting values
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Dim randomizer As New Random()
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Dim A As Integer = randomizer.Next(10, 20)
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Dim B As Integer = randomizer.Next(0, 20)
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Dim C As Integer = randomizer.Next(0, 5)
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'Let's display the initial values for comparison
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Console.WriteLine($"A value before If: {A}")
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Console.WriteLine($"B value before If: {B}")
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Console.WriteLine($"C value before If: {C}")
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' If A > 10, execute the three colon-separated statements in the order
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' that they appear
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If A > 10 Then A = A + 1 : B = B + A : C = C + B
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If A > 10 Then A = A + 1 : B = B + A : C = C + B
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'If the condition is true, the values will be different
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Console.WriteLine($"A value after If: {A}")
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Console.WriteLine($"B value after If: {B}")
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Console.WriteLine($"C value after If: {C}")
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End Sub
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End Module
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'This example displays output like the following:
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'A value before If: 11
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'B value before If: 6
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'C value before If: 3
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'A value after If: 12
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'B value after If: 18
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'C value after If: 21

‎docs/visual-basic/language-reference/statements/if-then-else-statement.md‎

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---
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title: "If...Then...Else Statement (Visual Basic)"
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ms.date: 07/20/2015
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ms.date: 04/16/2018
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ms.prod: .net
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ms.reviewer: ""
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ms.suite: ""
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ms.technology:
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- "devlang-visual-basic"
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ms.topic: "article"
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ms.topic: "conceptual"
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f1_keywords:
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- "vb.ElseIf"
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- "vb.Then"
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## Syntax
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```
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' Multiple-line syntax:
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' Multiline syntax:
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If condition [ Then ]
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[ statements ]
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[ ElseIf elseifcondition [ Then ]
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' Single-line syntax:
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If condition Then [ statements ] [ Else [ elsestatements ] ]
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```
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## Quick links to example code
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This article includes several examples that illustrate uses of the `If`...`Then`...`Else` statement:
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* [Multiline syntax example](#multi-line)
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* [Nested syntax example](#nested)
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* [Single-line syntax example](#single-line)
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## Parts
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`condition`
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Required. Expression. Must evaluate to `True` or `False`, or to a data type that is implicitly convertible to `Boolean`.
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If the expression is a [Nullable](../../../visual-basic/programming-guide/language-features/data-types/nullable-value-types.md)`Boolean` variable that evaluates to [Nothing](../../../visual-basic/language-reference/nothing.md), the condition is treated as if the expression is not `True`, and the `Else` block is executed.
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If the expression is a [Nullable](../../../visual-basic/programming-guide/language-features/data-types/nullable-value-types.md) `Boolean` variable that evaluates to [Nothing](../../../visual-basic/language-reference/nothing.md), the condition is treated as if the expression is `False` and the `Else` block is executed.
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`Then`
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Required in the single-line syntax; optional in the multiple-line syntax.
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Required in the single-line syntax; optional in the multiline syntax.
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`statements`
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Optional. One or more statements following `If`...`Then` that are executed if `condition` evaluates to `True`.
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Optional. One or more statements that are executed if no previous `condition` or `elseifcondition` expression evaluates to `True`.
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`End If`
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Terminates the `If`...`Then`...`Else` block.
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Terminates the multiline version of `If`...`Then`...`Else` block.
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## Remarks
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## Multiple-Line Syntax
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When an `If`...`Then`...`Else` statement is encountered, `condition` is tested. If `condition` is `True`, the statements following `Then` are executed. If `condition` is `False`, each `ElseIf` statement (if there are any) is evaluated in order. When a `True``elseifcondition` is found, the statements immediately following the associated `ElseIf` are executed. If no `elseifcondition` evaluates to `True`, or if there are no `ElseIf` statements, the statements following `Else` are executed. After executing the statements following `Then`, `ElseIf`, or `Else`, execution continues with the statement following `End If`.
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### Multiline syntax
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When an `If`...`Then`...`Else` statement is encountered, `condition` is tested. If `condition` is `True`, the statements following `Then` are executed. If `condition` is `False`, each `ElseIf` statement (if there are any) is evaluated in order. When a `True` `elseifcondition` is found, the statements immediately following the associated `ElseIf` are executed. If no `elseifcondition` evaluates to `True`, or if there are no `ElseIf` statements, the statements following `Else` are executed. After executing the statements following `Then`, `ElseIf`, or `Else`, execution continues with the statement following `End If`.
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The `ElseIf` and `Else` clauses are both optional. You can have as many `ElseIf` clauses as you want in an `If`...`Then`...`Else` statement, but no `ElseIf` clause can appear after an `Else` clause. `If`...`Then`...`Else` statements can be nested within each other.
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In the multiple-line syntax, the `If` statement must be the only statement on the first line. The `ElseIf`, `Else`, and `End If` statements can be preceded only by a line label. The `If`...`Then`...`Else` block must end with an `End If` statement.
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In the multiline syntax, the `If` statement must be the only statement on the first line. The `ElseIf`, `Else`, and `End If` statements can be preceded only by a line label. The `If`...`Then`...`Else` block must end with an `End If` statement.
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> [!TIP]
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> The [Select...Case Statement](../../../visual-basic/language-reference/statements/select-case-statement.md) might be more useful when you evaluate a single expression that has several possible values.
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## Single-Line Syntax
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You can use the single-line syntax for short, simple tests. However, the multiple-line syntax provides more structure and flexibility and is usually easier to read, maintain, and debug.
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### Single-Line syntax
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You can use the single-line syntax for a single condition with code to execute if it's true. However, the multiple-line syntax provides more structure and flexibility and is easier to read, maintain, and debug.
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What follows the `Then` keyword is examined to determine whether a statement is a single-line `If`. If anything other than a comment appears after `Then` on the same line, the statement is treated as a single-line `If` statement. If `Then` is absent, it must be the start of a multiple-line `If`...`Then`...`Else`.
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In the single-line syntax, you can have multiple statements executed as the result of an `If`...`Then` decision. All statements must be on the same line and be separated by colons.
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## Example
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The following example illustrates the use of the multiple-line syntax of the `If`...`Then`...`Else` statement.
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[!code-vb[VbVbalrStatements#101](../../../visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_1.vb)]
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## Example
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## Multiline syntax example
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<a name="multi-line"></a>
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The following example illustrates the use of the multiline syntax of the `If`...`Then`...`Else` statement.
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[!code-vb[VbVbalrStatements#101](../../../visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_1.vb?highlight=11,14,17,19)]
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## Nested syntax example
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<a name="nested"></a>
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The following example contains nested `If`...`Then`...`Else` statements.
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[!code-vb[VbVbalrStatements#102](../../../visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_2.vb)]
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[!code-vb[VbVbalrStatements#102](../../../visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_2.vb?highlight=14,15,17,19,20,21,23,25,26,28)]
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## Single-Line syntax example
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## Example
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<a name="single-line"></a>
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The following example illustrates the use of the single-line syntax.
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[!code-vb[VbVbalrStatements#103](../../../visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_3.vb)]
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[!code-vb[VbVbalrStatements#103](../../../visual-basic/language-reference/error-messages/codesnippet/VisualBasic/if-then-else-statement_3.vb?highlight=18)]
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## See Also
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## See also
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<xref:Microsoft.VisualBasic.Interaction.Choose%2A>
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<xref:Microsoft.VisualBasic.Interaction.Switch%2A>
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[#If...Then...#Else Directives](../../../visual-basic/language-reference/directives/if-then-else-directives.md)

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