Here, using the MustInherit keyword, we can create an abstract class. An abstract class includes a method that is abstract. The MustOverride keyword is used to create abstract methods here.Program :
Below is the source code to demonstrate the abstract class. The program given is compiled and successfully executed.
'VB.net program to demonstrate the abstract class.
Module Module1 MustInherit Class Sample1 MustOverride Sub Fun1() MustOverride Sub Fun2() End Class Class Sample2 Inherits Sample1 Overrides Sub Fun1() Console.WriteLine("Override method Fun1() called") End Sub Overrides Sub Fun2() Console.WriteLine("Override method Fun2() called") End Sub End Class Sub Main() Dim S As New Sample2() S.Fun1() S.Fun2() End Sub End Module
We created a Module1 module in the program above that comprises two classes, Sample1 and Sample2.
Here, an abstract class comprising two abstract methods is Sample1. The object of an abstract class can not be created. Here, the Sample1 class methods are overridden in the Sample2 class.
Finally, we created a Main() function, which is the program entry point, where we created the Sample2 class object, and called both Fun1() and Fun2() methods, which will print the required message on the console screen.