/optionexplicit

Causes the compiler to report errors if variables are not declared before they are used.

/optionexplicit[+ | -]

Arguments

• + | -
  Optional. Specify /optionexplicit+ to require explicit declaration of variables. The /optionexplicit+ option is the default and is the same as /optionexplicit. The /optionexplicit- option enables implicit declaration of variables.

Remarks

If the source code file contains an Option Explicit Statement (Visual Basic), the statement overrides the /optionexplicit command-line compiler setting.

To set /optionexplicit in the Visual Studio IDE

1. Have a project selected in Solution Explorer. On the Project menu, click Properties. For more information, see Introduction to the Project Designer.

2. Click the Compile tab.

3. Modify the value in the Option Explicit box.

Example

The following code compiles when /optionexplicit- is used.

Module Module1
    Sub Main()
        i = 99
        System.Console.WriteLine(i)
    End Sub
End Module

See Also

Reference

/optioncompare

/optionstrict

/optioninfer

Sample Compilation Command Lines (Visual Basic)

Option Explicit Statement (Visual Basic)

Visual Basic Defaults, Projects, Options Dialog Box

Other Resources

Visual Basic Command-Line Compiler

Change History

Date	History	Reason
January 2011	Clarified use of the Option Explicit statement.	Information enhancement.