Duplicated string literals make the process of refactoring error-prone, since you must be sure to update all occurrences.

On the other hand, constants can be referenced from many places, but only need to be updated in a single place.

Noncompliant Code Example

Public Class Foo

    Private Name As String = "foobar" ' Noncompliant

    Public ReadOnly Property DefaultName As String = "foobar" ' Noncompliant

    Public Sub New(Optional Value As String = "foobar") ' Noncompliant

        Dim Something = If(Value, "foobar") ' Noncompliant

    End Sub

End Class

Compliant Solution

Public Class Foo

    Private Const Foobar As String = "foobar"

    Private Name As String = Foobar

    Public ReadOnly Property DefaultName As String = Foobar

    Public Sub New(Optional Value As String = Foobar)

        Dim Something = If(Value, Foobar)

    End Sub

End Class

Exceptions

The following are ignored:

• literals with fewer than 5 characters
• literals matching one of the parameter names
• literals used in attributes