Question

I have to solve next problem:

Form23:

public
 { Public declarations }
 FormsArray : array of TForm24;
end;


Procedure Create_form;
begin
 SetLength(FormsArray, Length(FormsArray)+1);
 FormsArray[Length(FormsArray)-1] := TForm24.Create(Self);
end;

Form24:

public
end;

var
 UniqueValue : Array of ShortString;

Procedure Fill_Unique;
var
 tmp1 : Longint;
begin
 SetLength(UniqueValue, 256);
 for tmp1 := 0 to Length(UniqueValue)-1 do
 begin
  UniqueValue[tmp1] := IntToStr(tmp1);
 end;
end;

Procedure OnButtonClick(Sender);
begin
 Fill_Unique;
end;

When i have one form Form24 and i fill with some values, then it is ok.

When i have two forms Form24 (FormsArray[0] and FormsArray[1]) and i change UniqueValue in one form, then i have that values in two forms.

i.e.

I create FormsArray[0] and FormsArray[1]

When I click button on FormsArray[0]:

FormsArray[0] – UniqueValue[…] = ‘1,2,3,4,5,6,7,8,9…’;

FormsArray[1] – UniqueValue[…] = ‘1,2,3,4,5,6,7,8,9…’;

When I click button on FormsArray[1]:

FormsArray[0] – UniqueValue[…] = ‘1,2,3,4,5,6,7,8,9…’;

FormsArray[1] – UniqueValue[…] = ‘1,2,3,4,5,6,7,8,9…’;

When i change code to:

Form24:

public
 UniqueValue : Array of ShortString;
end;

and I click button on FormsArray[1] then i have:

FormsArray[0] – UniqueValue[…] = ”;

FormsArray[1] – UniqueValue[…] = ”;

UniqueValue is empty.

I need to have independent arrays in every forms Form24 i have created (different UniqueValue in every forms i create).

How to do this? What i do wrong?

Thanks for any help.

SOLVED !

I got -1 for solution what i write here. Then will be no solution. Search for yourself.

Answer 1

It sounds like you’ve already solved it. Make UniqueValue be a member of the form class. Put it in the public section of the class declaration, for example.

type
  TForm24 = class(TForm)
  public
    UniqueValue: array of string;
  end;

The first code you showed has the array as a global variable, which is of course shared by all instances of your form class, as well as everything else in your program. You’re probably confused thinking that anything declared in the same file as the form class somehow “belongs to” that class, but if you think that, you’re mistaken. To make something belong to a class, it should be declared inside that class, not just somewhere in the same unit file.

It looks like you’ll probably want to make Fill_Unique and OnButtonClick be members of the form class, too. In the code you showed, they’re standalone procedures, so they have no reference to whatever form they’re supposed to work on. That means they can’t refer to UniqueValue because they won’t know which TForm24 instance’s field to operate on.