60 lines
1.4 KiB
Plaintext
60 lines
1.4 KiB
Plaintext
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There are several compilations options available for Visual Basic source code and ``Option Strict`` defines compiler behavior for implicit data type conversions. Specifying ``Option Strict Off`` will allow:
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* Implicit narrowing conversions
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* Late binding
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* Implicit typing that results in an ``Object`` type
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This behavior can lead to unexpected runtime errors due to type mismatch or missing members.
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``Option Strict`` can be set in project properties or overridden in individual source files.
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== Noncompliant Code Example
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----
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Option Strict Off ' Noncompliant
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Public Class KnownType
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Public ReadOnly Property Name As String
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End Class
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Public Module MainMod
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Public Function DoSomething(Arg) As String ' Type for "Arg" argument is not defined.
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Dim Item As KnownType = Arg ' Implicit narrowing conversion doesn't enforce "Arg" to be of type "KnownType"
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Return Arg.Title ' "Title" might not exist in "Arg"
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End Function
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End Module
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----
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== Compliant Solution
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----
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Option Strict On
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Public Class KnownType
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Public ReadOnly Property Name As String
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End Class
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Public Module MainMod
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Public Function DoSomething(Arg As KnownType) As String
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Dim Item As KnownType = Arg
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Return Arg.Name
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End Function
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End Module
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----
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== See
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* https://docs.microsoft.com/en-us/dotnet/visual-basic/language-reference/statements/option-strict-statement
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