Can we override private virtual method in c#?

No, we cannot override a private virtual method in C#.Even we cannot access private methods of base class in derived, so the overridden of private virtual method is not possible.

In order to override a method, it must be marked with the 'virtual' keyword in the base class and then overridden in a derived class using the override keyword. However, the virtual modifier is not accessible outside the class in which it is declared, including derived classes.

Private methods are not accessible to derived classes, so it is not possible to override them. The virtual modifier is typically used to allow derived classes to provide their own implementation of a method, but since private methods are not visible to derived classes, there is no way to override them.

Here's an example to illustrate the point:

public class BaseClass
{
    private virtual void PrivateVirtualMethod()
    {
        // Error: virtual or abstract member cannot be private 
    }
}

public class DerivedClass : BaseClass
{
    // This is not allowed, as the private method cannot be overridden
    private override void PrivateVirtualMethod()
    {
        // Method implementation in derived class
    }
}

In this example, attempting to override the 'PrivateVirtualMethod' in the 'DerivedClass' will result in a compilation error because the private method in the base class is not accessible in the derived class.

In this example, even though you're using the 'override' keyword in the 'DerivedClass', the method in the 'DerivedClass' doesn't actually override the 'PrivateVirtualMethod' in the 'BaseClass'. As a result, when calling the method through instances of both classes, you'll always get the output of the 'PrivateVirtualMethod' in the 'BaseClass'.

Remember that for method overriding to work, the method in the base class needs to have a visibility modifier that allows access from the derived class, such as 'protected' or 'internal', but not private.