Jaymol
asked on
Basic class with "private" variables.
Hi.
I've created a class for use in an application and I'm having problems understanding the point of the word "private", as it seems to make no difference.
For example, here's a small class that shows my problem...
type
TTestClass = class
private
_Name : String;
procedure SetName(Value: String);
public
property Name : String read _Name write SetName;
end;
procedure TTestClass.SetName(Value: String);
begin
_Name := Value;
end;
if I create an instance of that class, then I would not expect to be able to do the following...
oTestClass := TTestClass.Create;
oTestClass._Name := 'Bob';
...but I can.
Can someone PLEASE tell me what the point of the "private" keyword is, AND how do I make a truly private variable that is for internal use within the class only?
Thanks in advance,
John.
PS. It's lots of points cos I need a quick answer.
I've created a class for use in an application and I'm having problems understanding the point of the word "private", as it seems to make no difference.
For example, here's a small class that shows my problem...
type
TTestClass = class
private
_Name : String;
procedure SetName(Value: String);
public
property Name : String read _Name write SetName;
end;
procedure TTestClass.SetName(Value: String);
begin
_Name := Value;
end;
if I create an instance of that class, then I would not expect to be able to do the following...
oTestClass := TTestClass.Create;
oTestClass._Name := 'Bob';
...but I can.
Can someone PLEASE tell me what the point of the "private" keyword is, AND how do I make a truly private variable that is for internal use within the class only?
Thanks in advance,
John.
PS. It's lots of points cos I need a quick answer.
atul_parmar
the scope of private is upto unit level not class level.
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ASKER
Okay, I see that now.
Is there simply no way to make private declarations actually private within the same unit then?
John.
Is there simply no way to make private declarations actually private within the same unit then?
John.
NO Not in Delphi 1-7. However, in Delphi 2005/2006 there is strict private what could make it. e.g.
...
strict private
_Name : String;
...
...
strict private
_Name : String;
...
ASKER
Ah well.
Guess I'll just have to bear that in mind for the future. I assumed that the variables weren't actually private, but will just stick things in separate units from now on.
Thanks for the help.
Guess I'll just have to bear that in mind for the future. I assumed that the variables weren't actually private, but will just stick things in separate units from now on.
Thanks for the help.