Cration of TShape causes access violation error

[bruce.button]

I am trying to create an array of circles (using TShape). However, when I run the code I get an Access violation error on the line (52):

   points[index] := TShape.Create(Application);

The complete code is below.

Thank you for this very helpful forum!

Code: Pascal  [Select][+][-]

1. unit main_form;
2.  
3. {$mode objfpc}{$H+}
4.  
5. interface
6.  
7. uses
8.         Classes, SysUtils, Forms, Controls, Graphics, Dialogs, ExtCtrls, StdCtrls;
9.  
10. type
11.         TPointArray = array of TShape;
12.  
13.         { TForm1 }
14.  
15.  TForm1 = class(TForm)
16.                 btn_Generate: TButton;
17.                 procedure btn_GenerateClick(Sender: TObject);
18.   procedure FormCreate(Sender: TObject);
19.         private
20.  
21.         public
22.  
23.         end;
24.  
25.  
26.  
27. var
28.         Form1: TForm1;
29.         points: TPointArray;
30.  
31.  
32.  
33. implementation
34.  
35. {$R *.lfm}
36.  
37. { TForm1 }
38.  
39. procedure TForm1.FormCreate(Sender: TObject);
40.  
41. begin
42.  
43. end;
44.  
45. procedure TForm1.btn_GenerateClick(Sender: TObject);
46. var
47.         i: integer;
48.  
49. begin
50.         for i := 1 to 20 do
51.         begin
52.                 points[i] := TShape.Create(Application);
53.                 points[i].Shape := stCircle;
54.                 points[i].left := 60 + 30 * i;
55.                 points[i].Top := 200;
56.                 points[i].width := 10;
57.                 points[i].height := 10;
58.                 points[i].Brush.Color := clRed;
59.         end;
60. end;
61.  
62. end.
63.  
64.  

[eljo]

1) I do not see any setlength call for the array
2) dynamic arrays alway start at position 0 not 1

something along the lines of.

Code: Pascal  [Select][+][-]

1. procedure TForm1.btn_GenerateClick(Sender: TObject);
2. var
3.         i: integer;
4.  
5. begin
6.   SetLength(Points, 20)
7.         for i := 0 to 19 do
8.         begin
9.                 points[i] := TShape.Create(Application);
10.                 points[i].Shape := stCircle;
11.                 points[i].left := 60 + 30 * i;
12.                 points[i].Top := 200;
13.                 points[i].width := 10;
14.                 points[i].height := 10;
15.                 points[i].Brush.Color := clRed;
16.         end;
17. end;

[bruce.button]

Thank you, Eljo, that solves the problem. Stupid mistake!