Confused on Encapsulation. Should I keep stabbing at it?

I am not into C# but I'll do my best to explan how I understand it.

Encapsulation is one of the fundamental principles of the OOP style.Protect your properties from outside access and allow outside access to them using methods.

Remember, properties store data and methods are there to interact with the properties, with the data.This interaction is made only by methods to assure your class is well structured.

When I use the term "outside", basically it means outside the class/object.

Why you would do something like this? Because someone, even you, can change the normal flow of a class by setting directly a value for a property, a value that breaks everything.

Let me give you a more clear example:

You have a class called Money.This class has a public property called amount and two methods: getAmount() and setAmount(amount).The first method returns the content of the amount property and the second one set the content of the amount property.The second method has some logic too, it checks if the amount is not a negative value, so we can't store negative values.

Great, thins are great until now, but we have one problem, the property amount has public visibilty, basically it means that I can directly modify the content of the amount property.What does it mean? I can set any value I want, even a negative one.Why I can do that? Because it has public visiblity, the logic from the setAmount() method is not used anymore, you see, this is a big problem, we don't want negative values, just 0 or any other greater value.

Iam giving you an example in PHP, wich is a little similar, OOP concepts are the same no matter wich language you use.

<?php

class Money
{
    public $amount = 0;

    public function getAmount()
   {
       return $this->amount;
   }

   public function setAmount(integer $amount = 0)
   {
      // the logic to check if the amount is not a negative value
       if ($amount < 0) {
           throw new Exception("The amount can be a negative value");
       }

      $this->amount = $amount;
   }
}

// we create an object for the Money class 
$money = new Money;

// we set the amount to 10 by using the setAmount() method 
$money->setAmount(10);

// it displays 10, great.
echo $money->getAmount();

// because the $amount property is public, we can access it directly outside the object 
// look at what I do, I set a negative value, 
$money->amount = - 10;

// it displays -10, I bypassed the rule without negative values.
echo $money->getAmount();

It can create tons of problems, set a different visibility for your properties and use methods to act on them.

Use methods like the one from above when interacting with properties, one gets the value of a property and one sets a value for a property.