C# Base

In C#, base keyword is used to access fields, constructors and methods of base class.

You can use base keyword within instance method, constructor or instance property accessor only. You can't use it inside the static method.

Accessing base class field

We can use the base keyword to access the fields of the base class within derived class. It is useful if base and derived classes have the same fields. If derived class doesn't define same field, there is no need to use base keyword. Base class field can be directly accessed by the derived class.

Example

Let's see the simple example of base keyword in C# which accesses the field of base class.

snippet

using System;
public class Animal{
    public string color = "white";
}
public class Dog: Animal
{
    string color = "black";
    public void showColor()
    {
        Console.WriteLine(base.color);
        Console.WriteLine(color);
    }
    
}
public class TestBase
{
    public static void Main()
    {
        Dog d = new Dog();
        d.showColor();
    }
}

Calling base class method

By the help of base keyword, we can call the base class method also. It is useful if base and derived classes defines same method. In other words, if method is overridden. If derived class doesn't define same method, there is no need to use base keyword. Base class method can be directly called by the derived class method.

Example

Let's see the simple example of base keyword which calls the method of base class.

snippet

using System;
public class Animal{
    public virtual void eat(){
        Console.WriteLine("eating...");
    }
}
public class Dog: Animal
{
    public override void eat()
    {
        base.eat();
        Console.WriteLine("eating bread...");
    }
    
}
public class TestBase
{
    public static void Main()
    {
        Dog d = new Dog();
        d.eat();
    }
}

Output

eating... eating bread...

Calling base class constructor internally

Whenever you inherit the base class, base class constructor is internally invoked. Let's see the example of calling base constructor.

Example

snippet

using System;
public class Animal{
    public Animal(){
        Console.WriteLine("animal...");
    }
}
public class Dog: Animal
{
    public Dog()
    {
        Console.WriteLine("dog...");
    }
    
}
public class TestOverriding
{
    public static void Main()
    {
        Dog d = new Dog();
        
    }
}

Output

animal... dog...