assigning a value to a global variable (Delphi)

Question

I am trying to access a global variable on a form that is one in an Array of Forms, I have tried using this:

max_forms := 3

setlength(form_array, max_forms);

form_array[1] := frm1;
form_array[2] := frm2;

if current_form > 0 then
begin
  form_array[current_form].fNumber := Number;
  form_array[current_form].ShowModal;
end;

The above does not work obviously. Any help would be greatly appreciated.

Answer 1

I guess the problem is that fNumber has private access.

Depending on the purpose of this field, one solution could be creating a property to gain write access:

property Number: Integer read FNumber write FNumber;

Then you can do the assignment:

form_array[current_form].Number := Number;

About global variables:

If this is in fact the problem and FNumber is the "global" variable you are talking about, then you are using the wrong words. FNumber is a field and belongs to a form. Form members are not global.

Look at the source of your form. If it has been generated by the Delphi IDE you'll find a variable declaration below it:

end; // End of TForm1

var
  Form1: TForm1;

implementation

Form1 is a real global variable, because it exists in the interface of a unit and outside of any class and you can access from anywhere (not a good thing in general) as for FNumber you first need access to a form instance.

PS: I don't know what exactly you are trying to achive, but perhaps you can take a look at Screen.Forms which provides a list of the active forms. That might be better suited than a custom list.