Inheritance in Visual Basic

Inherits, Overridable and MyBase in a two-class hierarchy.

Dim probes As Sensor() = {New Sensor(), New Thermometer()}
For Each p In probes
    Console.WriteLine(p.Describe())
Next

Class Sensor
    Public Overridable Function Describe() As String
        Return "generic sensor"
    End Function
End Class

Class Thermometer
    Inherits Sensor

    Public Overrides Function Describe() As String
        Return MyBase.Describe() & ", tuned for heat"
    End Function
End Class

How it works

1. Overridable invites replacement; Overrides accepts.
2. Inherits Sensor takes everything the parent defined.
3. MyBase.Describe() starts from the parent's answer and extends it.

Keywords and builtins used here

• Class
• Describe
• Dim
• Each
• End
• For
• Function
• Inherits
• MyBase
• New
• Next
• Overridable
• Overrides
• Public
• Return
• Sensor
• String
• Thermometer

The run, in numbers

Lines

18

Characters to type

378

Tokens

78

Three-star pace

90 tpm

At the three-star pace of 90 tokens a minute, this run takes about 52 seconds.

Type this snippet

Step 2 of 3 in Classes & interfaces, step 17 of 29 in Language basics.

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Inheritance in other languages

• C#
• Java