Method overriding – Using override keyword in child
class, Re-implementing the logic of base class method and hiding the base
method.
Method Hiding – Using new keyword in child class hiding the
own method.
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace MethodOverridingVsHiding
{
class BaseClass
{
public BaseClass()
{
Console.WriteLine("Base
Class Constructor.");
}
public void Print()
{
Console.WriteLine("Base
Class Print Method.");
}
public void BaseDisplay()
{
Console.WriteLine("Base
Class Display Method.");
}
}
class ChildClass : BaseClass
{
public ChildClass()
{
Console.WriteLine("Child
Class Constructor.");
}
public void Print()
{
Console.WriteLine("Child
Class Print Method.");
}
public void ChildDisplay()
{
Console.WriteLine("Child
Class Display Method.");
}
static void Main(string[]
args)
{
// create object here
Console.ReadLine();
}
}
}
Step 1:- Create object of Base Class
BaseClass objBaseClass = new BaseClass();
objBaseClass.Print();
objBaseClass.BaseDisplay();
Output
Base Class Constructor.
Base Class Print Method.
Base Class Display Method.
Note:-
1. If
you create the object of the base class, it will access all method in the base
class.
2. If the class using constructor, it will call first and
then the method calling sequence.
Step 2:- Create object of Child Class
ChildClass objChildClass = new ChildClass();
objChildClass.Print();
objChildClass.BaseDisplay();
objChildClass.ChildDisplay();
Output
Base Class Constructor.
Child Class Constructor.
Child Class Print Method.
Base Class Display Method.
Child Class Display Method.
Note:-
1. If
a child class inherits the base class and you are creating the object of the
child class, its access all method of the base class as well as its own method.
2. If
base class any method with same name exists in the child class, it’s called the
own method.
3. If
you want to still call the base method use the new keyword, new keyword tells
the compiler to hide the child method and call the base method.
4. If
the classes using constructor, it will call first base class constructor and
then the child constructor.
Note (For Point 3):
1. If
you are using the new keyword in child class for hiding method intentional,
check base class method marked virtual or not.
2. If
base class method not marked virtual, still it's called child class method.
Do following Changes:
In Base class mark Print method as virtual
public virtual
void Print()
{
Console.WriteLine("Base
Class Print Method.");
}
In Child class mark Print method as new
public new
void Print()
{
Console.WriteLine("Base
Class Print Method.");
}
Step 3:- Create object of Base Class that reference to object of
Child class
BaseClass objBaseChild = new ChildClass();
objBaseChild.Print();
objBaseChild.BaseDisplay();
Output
Base Class Constructor.
Child Class Constructor.
Base Class Print Method.
Base Class Display Method.
Note:-
1. If
you create the object of the base class that reference to object of a child
class, its access the all method of the base class as well as overriding
methods of the child.
2. If
base class any method with same name exists in the child class, it’s called the
base class method.
3. If
you want to still call the child method use the override keyword, override
keyword tells the compiler to hide the base method and call the child method.
4. If
the classes using constructor, it will call first base class constructor and
then the child constructor.
Note (For Point 3):
1. If
you are using the override keyword in child class, check base class method
marked virtual or not.
2. If base class method not marked virtual, you will get
the runtime error.
Do following Changes:
In Base class mark Print method as virtual
public virtual
void Print()
{
Console.WriteLine("Base
Class Print Method.");
}
In Child class mark Print method as new
public override
void Print()
{
Console.WriteLine("Base
Class Print Method.");
}
