What are the key points to make the method as overridden?
To make a method eligible for overriding in C#, you need to consider the following key points:
-
Inheritance: The method you want to override should be defined in a base (parent) class and accessible to the derived (child) class. In other words, the derived class should inherit from the base class that declares the method.
-
Virtual or abstract modifier: The method in the base class must be marked with either the 'virtual' or 'abstract' modifier.
-
'virtual' methods provide a default implementation in the base class and allow derived classes to override them with their own implementations. The base class implementation can be invoked using the base keyword within the derived class.
-
'abstract' methods, on the other hand, do not provide an implementation in the base class. They simply declare the method's signature, and all derived classes are required to provide an implementation by overriding them.
-
Method signature: The overriding method in the derived class must have the same method name, return type, and parameter list (including parameter types and order) as the base class method.
-
Access modifiers: The access modifier of the overriding method in the derived class should be the same or more accessible than the base class method. For example, if the base class method is 'public', the overriding method can be 'public' or 'protected', but not 'private'.
-
'override' keyword: When overriding a method in the derived class, you need to use the 'override' keyword to indicate that you are intentionally providing a new implementation for the base class method. This ensures that the method is explicitly marked as overridden.
By following these key points, you can properly override a method in C# to provide a new implementation in the derived class while leveraging the polymorphic behavior of object-oriented programming.