What's the Difference Between Shadowing and Overriding in C# Inheritance?

C# inherited Shadowing and Overriding Differential Explanation

In the inheritance mechanism, programmers will encounter two very different technologies: Shadowing (Hidden) and Overriding. Understanding the subtle difference between the two is essential for effective use of inheritance.

overriding

When a method occurs in a subclass statement, the method defined in the base class has the same name, return type, and parameter list. Rewriting allows the custom implementation of the base class method. When the sub -class object calls the rewriting method, the code in the subclass will effectively cover the behavior of the base class method. In contrast,

Shadowing

When a method occurs in a subclass statement, the method of this method has the same name as the method in the base class, but the method signature (return type or parameter list) different. A new method is hidden in the subclass, which replaces the method with the same name in the base class. Call the hidden method on the object of the subclass to perform the code in the subclass, effectively hiding the base method. Consider the following example:

When calling the method on the objects of Class A and B, the expected output is as follows:

class A {
   public int Foo() { return 5; }
   public virtual int Bar() { return 5; }
}
class B : A {
   public new int Foo() { return 1; }     // 隐藏
   public override int Bar() { return 1; } // 重写
}

The key difference is when converting the B object to an object:

A clA = new A();
B clB = new B();

Console.WriteLine(clA.Foo()); // 输出：5
Console.WriteLine(clA.Bar()); // 输出：5
Console.WriteLine(clB.Foo()); // 输出：1
Console.WriteLine(clB.Bar()); // 输出：1

// 将 B 转换为 A
Console.WriteLine(((A)clB).Foo()); // 输出：5

For hidden methods (FOO), call the realization of the base class.

• For the rewriting method (BAR), call the implementation of the subclass.
hidden (shadowing)

If the base method is dependent in the code that is not considered, there may be problems. It may cause accidental behavior and make debugging difficult. On the other hand, Overriding

provides a controlled mechanism to modify the method to implement, while maintaining the inheritance structure.

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