How to forbid the use of fields instead of properties? [duplicate]

Question

I have a property in my class that has a lot of logic in set accessor:

private String text;

public String Text
{
   get { return text; }
   private set
   {
      // some actions with a value
      value = value.Replace('a', 'b');

      text = value;
   }
}

How can I prevent other developers (or even me) from changing field instead of property inside of this class ?

If somebody writes something like this:

public Test(String text)
{
   this.text = text;
}

it will break the logic of my class !

Answer 1

There is a correct way to do this. Consider the old adage "All problems in computer science can be solved by another level of indirection".

What you do is create a class that knows how to set the value of the text field properly.

class TextSetter
{
    private string text;
    public TextSetter(string text)
    {
        Text = text;
    }
    public string Text
    {
        get{ return text;}
        set{ text = value.Replace('a', 'b');}
    }
}

Then in your first class instead of private string text; you have private TextSetter text; now there is never any chance that someone will accidentally set the value directly.

you could even generalise this, if it's a common problem

class FieldSetter<T>
{
    private T field;
    private Func<T, T> setter;
    public FieldSetter(Func<T, T> setter, T field)
    {
        this.setter = setter
        Value = field;
    }
    public T Value
    {
        get{ return field;}
        set{ field = setter(value);}
    }
}

Feel free to rename as you see fit.