rspec/rules/S3655/vbnet/rule.adoc

== Why is this an issue?


Nullable value types can hold either a value or `Nothing`. The value stored in the nullable type can be accessed with the `Value` property or by casting it to the underlying type. Still, both operations throw an `InvalidOperationException` when the value is `Nothing`. A nullable type should always be tested before the value is accessed to avoid the exception.

=== Noncompliant code example

[source,vbnet]
----
Sub Sample(condition As Boolean)
    Dim nullableValue As Integer? = If(condition, 42, Nothing)
    Console.WriteLine(nullableValue.Value)             ' Noncompliant

    Dim nullableCast As Integer? = If(condition, 42, Nothing)
    Console.WriteLine(CType(nullableCast, Integer))    ' Noncompliant
End Sub
----

=== Compliant solution

[source,vbnet]
----
Sub Sample(condition As Boolean)
    Dim nullableValue As Integer? = If(condition, 42, Nothing)
    If nullableValue.HasValue Then
        Console.WriteLine(nullableValue.Value)
    End If
            
    Dim nullableCast As Integer? = If(condition, 42, Nothing)
    If nullableCast.HasValue Then
        Console.WriteLine(CType(nullableCast, Integer))
    End If
End Sub
----

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== Comments And Links
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