force get/set access of private variables for private properties

Question

If I have a private variable that I want to have some internal validation on, and I want to keep that validation in one place, I put it behind a getter/setter and only access it thorugh that getter/setter. That's useful when dealing with public properties, because the other code cannot access the private variable, but when I'm dealing with object inside the class itself, is there any way to enforce the getter/setter?

  private int _eyeOrientation;

  private int eyeOrientation
  {
     get
     {
        return _eyeOrientation;
     }
     set
     {
        if (value < 0)
        {
           _eyeOrientation = 0;
        }
        else
        {
           _eyeOrientation = value % 360;
        }
     }
  }

The issue here being that the other functions in the class may accidentally modify

_eyeOrientation = -1;

which would throw the program into a tizzy. Is there any way to get that to throw a compiler error?

Answer 1

Sounds like you need a angle type.

// Non mutable Angle class with a normalized, integer angle-value
public struct Angle
{
  public Angle(int value)
  {
    Value = value;
  } 

  private angle;
  public Value 
  { 
    get { return angle; } 
    private set { angle = Normalize(value); } 
  }

  public static int Normalize(int value)
  {
     if (value < 0) return 360 - (value % 360);
     return value % 360;
  }
}

public class SomeClass
{
  public Angle EyeOrientation { get; set; }
}

If you have a certain kind of value, like angles, money, weight or whatever, it is always a good praxis to make it a own type, even if the value itself is stored in a int, decimal etc. This type makes your interfaces clearer and typesafe. It is not the same if you expect an Angle or a integer value as argument of some method.