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


-optionexplicit[+ | -]  


+ | -
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.


If the source code file contains an Option Explicit statement, 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.

  2. Click the Compile tab.

  3. Modify the value in the Option Explicit box.


The following code compiles when -optionexplicit- is used.

Module Module1
    Sub Main()
        i = 99
    End Sub
End Module

See also