Enforces strict type semantics to restrict implicit type conversions.


/optionstrict[+ | -]  


+ | -
Optional. The /optionstrict+ option restricts implicit type conversion. The default for this option is /optionstrict-. The /optionstrict+ option is the same as /optionstrict. You can use both for permissive type semantics.

Required. Warn when strict language semantics are not respected.


When /optionstrict+ is in effect, only widening type conversions can be made implicitly. Implicit narrowing type conversions, such as assigning a Decimal type object to an integer type object, are reported as errors.

To generate warnings for implicit narrowing type conversions, use /optionstrict:custom. Use /nowarn:numberlist to ignore particular warnings and /warnaserror:numberlist to treat particular warnings as errors.

To set /optionstrict 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 Strict box.

To set /optionstrict programmatically


The following code compiles Test.vb using strict type semantics.

vbc /optionstrict+ test.vb  

See Also

Visual Basic Command-Line Compiler
/warnaserror (Visual Basic)
Sample Compilation Command Lines
Option Strict Statement
Visual Basic Defaults, Projects, Options Dialog Box