VB .NET Language in a Nutshell

Name

#If...Then...#Else Directive

Syntax

#Ifexpression Then
   statements
[#ElseIf furtherexpression Then
   [elseifstatements]]
[#Else
   [elsestatements]]
#End If

expression

Use: Required

An expression made up of literals, operators, and conditional compiler constants that will evaluate to True or False

statements

Use: Required

One or more lines of code or compiler directives, which is executed if expressionevaluates to True

furtherexpression

Use: Optional

An expression made up of literals, operators, and conditional compiler constants that will evaluate to True or False. furtherexpression is only evaluated if the preceding expression evaluates to False

elseifstatements

Use: Optional

One or more lines of code or compiler directives, which is executed if furtherexpression evaluates to True

elsestatements

Use: Optional

One or more lines of code or compiler directives, which are executed if expression or furtherexpression evaluates to False

Description

Defines a block or blocks of code that are only included in the compiled application when a particular condition is met, allowing you to create more than one version of the application using the same source code.

Conditionally including a block of code is a two-step process:

• Use the #Const directive to assign a value to a conditional compiler constant.

• Evaluate the conditional compiler constant using the #If...Then...#End If statement block.

Only code blocks whose expressions evaluate to True are included in the executable. You can use the #Else ...