Why use property in a class?

Question

I was just wondering about why should I use property in a class instead of \"normal\" variables (class attributes?). What I mean is this:

TSampleClass = clas         


        

Answer 1

You cant monitor the change in a variable without a property.

your read/writes for property dont have to be a variable they can be functions. And then you can manage the "onChange" of a property.

eg

TmyChange = procedure(Sender: Tobject) of object;


private 
Fchange : TmyChange;

public
property SomeInfo: integer read getFoo write setFoo;
property onChange : TmyChange read Fchange write Fchange;

function getFoo : integer
begin
  return localFoo;
end;

function setFoo (value : integer)
begin
  // validate incoming value
   localFoo=value;
  if assigned(Fchange) then Fchange(self);
end;