[DUG] basic question

[Neven MacEwan]

Ani

What you are referring to is a "Class Method" and no Delphi does not 
have them (though other OO languages do)
it also does not have class variables (hence there is not need for Class 
Methods is the logic I presume)

The reason your code works is that the method you called makes no 
reference to the instance of FormB only to the method
of class FormB (and ShowMessage is a non OO procedure), in compiled code 
there always on instance of the code base (and data
for the Object instances) so i assume that you called "Execute" in the 
class method table in the context of a nil instance
If you had done

   procedure TFormB.Execute;
    begin
      ShowMessage(self.Caption); // AV Here
    end;

I'm sure this is all wrong and Max or Paul will correct me

Cheers
Neven

> Hi,
>
> Is it possible to call a method of a class without creating a object 
> of it, even if the method is not a class function in Delphi ? I wrote 
> the below code just to test -
>
> 1. Created a simple form A and a button on it.
> 2. Created another simple form B, written a procedure in it as -
>     FormB.Execute;
>     begin
>       ShowMessage("xyz");
>     end;
> 3. Commented out auto creation of FormB in application.
> 4. On Button Click in FormA I called the Execute of FormB and it 
> worked perfectly okay.
>
> What could be the reason for this? I had the idea that either I need 
> to create an object before calling any method or I need to declare a 
> class function.
>
> In the above steps when I am trying to call Show in Execute function 
> of Form B I got Access violation which is perfectly fine according to 
> the above statement.
>
> May be I am missing something simple here, but any pointers will be 
> great. This was done in D2005 and it's win32 app.
>
> Thanks
> -Ani
>
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