SRL Archive - Delphi/FPC Help and Tutorials

i'm trying to make an onclick event for a dynamical form. But it won't work, it alsways gives an error 'identifier not found'
i've searched around on different places and i used their help but nothing seemed to help me out

here is the script:

unit unit22;

{$mode objfpc}{$H+}

interface


uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

  { TForm2 }

  TForm2 = class(TForm)
    Procedure Nieuw(Sender: TObject);
  private
    { private declarations }

  public
    { public declarations }


  end;
var
  Form2: TForm2;
  Label2: Tlabel;
  Button2: Tbutton;
  Labels: Array of TLabel;
  Buttons: Array of Tbutton;
  i: integer;
  AantalStammen: integer;
  Stammen: Array of String;

Procedure Test2;



implementation

Procedure TForm2.Nieuw(Sender: TObject);
begin
  showmessage('nieuwe stam');
end;

Procedure Test2;
begin

  SetLength(Labels, AantalStammen-1);
  SetLength(Buttons, 3);
  if AantalStammen>1 then
  for i:= 0 to AantalStammen-1 do
  begin
  Labels[i]:=TLabel.Create(Label2);
  try
    with Labels[i] do
    begin
      Parent:=Form2;
      Left:=50;
      Top:=10+25*(i);
      Labels[i].Caption:=  Stammen[i] ;
    end;
  except
    Labels[i].Free;
  end;
  end;

  Form2.height:=AantalStammen*25+75;
  for i:= 0 to 2 do
  begin
  Buttons[i]:=Tbutton.Create(Button2);
  try
    with Buttons[i] do
    begin
      Buttons[i].Parent:=Form2;
      Buttons[i].width:=100;
      Buttons[i].height:=25;
      Buttons[i].Left:=25+(125*i);
      Buttons[i].Top:=Form2.height-50;

    end;
  except
    Buttons[i].Free;
  end;
  end;
  Buttons[0].Caption:= 'Nieuw';
  Buttons[1].Caption:= 'Wijzigen';
  Buttons[2].Caption:= 'Sluiten';
  Buttons[0].OnClick:= Nieuw;

  Form2.width:=3*125+25;
  Form2.show;
end;


{$R *.lfm}

end.

You didn't call TForm2.Create?

This is my main script, through which i call Tform2 with a button:

unit unit21;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls, unit22;

type

  { TForm1 }

  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { private declarations }
  public
    { public declarations }
  end;

var
  Form1: TForm1;
  UserFile : TextFile;
  FileName, TFile : String;


implementation

{$R *.lfm}

procedure TForm1.Button1Click(Sender: TObject);
Var
  i: integer;
Begin
 i:=0;
 GetDir(0,Filename);
 Filename:= Filename+'\Stammen.txt';
 AssignFile(UserFile,Filename);
 If not fileexists(Filename) then
 Rewrite(UserFile);
 Reset(UserFile);
 Repeat
  setlength(stammen,i+1);
  Readln(UserFile,TFile);
  stammen[i]:= Tfile;
  i:= i +1;
 Until Eof(UserFile);
 AantalStammen:=i;
 //showmessage('stammen:'+inttostr(AantalStammen));
 Test2;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin

end;

end.

I've added Tform.create but didn't help

unit unit22;

{$mode objfpc}{$H+}

interface


uses
  Classes, SysUtils, FileUtil, Forms, Controls, Graphics, Dialogs, StdCtrls;

type

  { TForm2 }

  TForm2 = class(TForm)
    //Procedure Nieuw(Sender: TObject);
  private
    { private declarations }

  public
    { public declarations }

  end;


var
  Form2: TForm2;
  Label2: Tlabel;
  Button2: Tbutton;
  Labels: Array of TLabel;
  Buttons: Array of Tbutton;
  i: integer;
  AantalStammen: integer;
  Stammen: Array of String;

Procedure Test2;



implementation

Procedure Nieuw(Sender: TObject);
begin
  showmessage('nieuwe stam');
end;

Procedure Test2;
begin
  Form2:= TForm2.create(nil);
  SetLength(Labels, AantalStammen-1);
  SetLength(Buttons, 3);
  if AantalStammen>1 then
  for i:= 0 to AantalStammen-1 do
  begin
  Labels[i]:=TLabel.Create(Label2);
  try
    with Labels[i] do
    begin
      Parent:=Form2;
      Left:=50;
      Top:=10+25*(i);
      Labels[i].Caption:=  Stammen[i] ;
    end;
  except
    Labels[i].Free;
  end;
  end;

  Form2.height:=AantalStammen*25+75;
  for i:= 0 to 2 do
  begin
  Buttons[i]:=Tbutton.Create(Button2);
  try
    with Buttons[i] do
    begin
      Buttons[i].Parent:=Form2;
      Buttons[i].width:=100;
      Buttons[i].height:=25;
      Buttons[i].Left:=25+(125*i);
      Buttons[i].Top:=Form2.height-50;

    end;
  except
    Buttons[i].Free;
  end;
  end;
  Buttons[0].Caption:= 'Nieuw';
  Buttons[1].Caption:= 'Wijzigen';
  Buttons[2].Caption:= 'Sluiten';
  Buttons[0].OnClick:= Nieuw;

  Form2.width:=3*125+25;
  Form2.show;
end;


{$R *.lfm}

end.

This has been solved using a pointer

type
TMethodPointer = packed record
pMethod: Pointer;
pObject: TObject;
end;

var
methodPointer: TMethodPointer;

in the code right before the event i place this (and make your onclick procedure):
methodPointer.pMethod := @Onclickprocedure;
methodPointer.pObject := nil;
Buttons[0].OnClick:= TNotifyEvent(methodPointer);

during the process of my program i will encounter several problems and now i have encountered this on:

during the creation of the program i will need to alter the main form.
My main form excists out of multiple buttons. But during the process i might add a few nieuw ones.
I would like to be able to changes the mainform at runtime.
If you start a new application then the mainform already has been made. But i would like to add buttons manually to the form.
But if i try this code then the mainform does not show the created components.
I have done some research. Their is stated that it's not possible to change the main form.
It should be created using Form1 := TForm1.Create(nil) instead of application.create(Tform1,form1) i've tried but it does not work. An other way is to hide the main form and use the 2nd as false mainform, but i haven't found a good explanation on how to do so

This would be the code :

begin
  NrOfButtons:= 4;
  setlength(buttons,NrOfButtons+1);

  for i:= 1 to NrOfButtons do
  begin
  Buttons[i]:=Tbutton.Create(Button2);
  try
    with Buttons[i] do
    begin
      Buttons[i].Parent:=Form1;
      Buttons[i].width:=100;
      Buttons[i].height:=25;
      Buttons[i].Top:= 25 + Buttons[i-1].Top+Buttons[i-1].height+15;
    end;
  except
    Buttons[i].Free;
  end;
  end;
  Buttons[1].Caption:='Gehouden Stammen';
  Buttons[4].OnClick:= TNotifyEvent(methodPointer);
  methodPointer.pMethod := @GehoudenStammen;
  methodPointer.pObject := nil;
  Buttons[2].Caption:='Nieuwe data';
  Buttons[3].Caption:='Print';
  Buttons[4].Caption:='Close';
  Buttons[4].OnClick:= TNotifyEvent(methodPointer);
  methodPointer.pMethod := @Close;
  methodPointer.pObject := nil;
  Form1.height:=25 + Buttons[length(buttons)].Top+Buttons[length(buttons)].height+15
end.