Private Virtual Methods

Question

Hi friends.... I know virtual methods but I want to know about private virtual methods ? Please explain with an example ? Thanks

Datta Kharad · Answer

Hi Private virtual method:- Private virtual methods cannot be declared in the C# language . In programming languages polymorphism based on types is a way to virtualize the entry point to a data object; for private methods you have already entered the data object and thus no virtualized entry point is ever required. In this example we see both a program that attempts to use a private virtual method member as well as the compile-time error that the program results in. As a reminder the error occurs during the static compilation phase which means that no program that declares a private virtual method will ever be executed in any way. Example of private virtual method():_ class A { private virtual int Test() { return 1; } } class Program { static void Main() { } } Compile-time error Error 1 'A.Test()': virtual or abstract members cannot be private. Notes. Virtual methods are an implementation of type-based polymorphism. When you have a derived class and a base class the derived class can re-implement the base class virtual method. This gives you a dynamic entry point to the class type which enables you to clearly separate the usage of the type from the implementation of each subtype. Instance private methods. Whenever a private method is invoked the type has already been entered—you can always define custom private methods on a type and if you are already inside the type you can simply call a regular instance private method. Further instance and static methods are faster to invoke than interface and virtual methods so there is a performance advantage to not using a private virtual method. Notice: Private virtual methods are allowed in the C++ programming language. They are used in some design patterns that emphasize the importance of overriding certain pieces of an algorithm only.