"protected" methods in C#?

Question

What are the benefits to defining methods as protected in C#?

like :

protected void KeyDemo_KeyPress( object sender, KeyPressEventArgs e )  {     // some code } 

As compared to something like this:

private void FormName_Click( object sender, EventArgs e ) {     //some code } 

I've seen such examples in many books and I don't understand why and when do they use private vs protected?

Answer 1

Protected methods can be called from derived classes. Private methods can't.

That's the one and only difference between private and protected methods.

Answer 2

Often 'protected' is used when you want to have a child class override an otherwise 'private' method.

public class Base {     public void Api() {        InternalUtilityMethod();     }     protected virtual void InternalUtilityMethod() {        Console.WriteLine("do Base work");     } }  public class Derived : Base {     protected override void InternalUtilityMethod() {        Console.WriteLine("do Derived work");     }  } 

So we have the override behavior we know and love from inheritance, without unnecessarily exposing the InternalUtilityMethod to anyone outside our classes.

var b = new Base(); b.Api();  // returns "do Base work" var d = new Derived(); d.Api(); // returns "do Derived work"