< nknabe.dk

Paradox BCD fields with Delphi 7 to Delphi XE and Delphi XE3

Editing and saving data in Paradox BCD fields in BDE/Paradox 32-bit applications compiled with Delphi XE3 evokes error [Number is out of range.] making BCD practically inaccessible in Delphi XE3 compiled paradox applications.
Results from test on same simple source code compiled with Delphi 7, Delphi 2009, Delphi XE and Delphi XE3, the compiled applications successively tested on Windows versions as shown.

The single form test application source code for PdxForm.pas:

unit PdxForm;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, DB, DBTables, Grids, DBGrids, DBCtrls, ExtCtrls, Menus;

type
  TForm1 = class(TForm)
    Database1: TDatabase;
    Table1: TTable;
    DataSource1: TDataSource;
    Panel1: TPanel;
    DBNavigator1: TDBNavigator;
    DBGrid1: TDBGrid;
    OpenDialog1: TOpenDialog;
    MainMenu1: TMainMenu;
    mnuFile: TMenuItem;
    mnuOpen: TMenuItem;
    mnuClose: TMenuItem;
    mnuExit: TMenuItem;
    mnuHelp: TMenuItem;
    mnuAbout: TMenuItem;
    procedure FormCreate(Sender: TObject);
    procedure mnuOpenClick(Sender: TObject);
    procedure mnuCloseClick(Sender: TObject);
    procedure mnuExitClick(Sender: TObject);
    procedure mnuAboutClick(Sender: TObject);
private
    { Private declarations }
public
    { Public declarations }
end;

var
  Form1: TForm1;
  slDbParams: TStringList;
  strDatabase: string;
  strTableName: string;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
  if Database1.Connected then
    Database1.Close;
  Database1.DatabaseName := 'DBConnection';
  OpenDialog1.Filter := 'Paradox Tables (*.db)|*.db';
  OpenDialog1.DefaultExt := '.db';
  OpenDialog1.InitialDir := ExtractFileDir(ParamStr(0)) + '\Data';
end;

procedure TForm1.mnuOpenClick(Sender: TObject);
begin
  if not OpenDialog1.Execute then
    exit;
  strDatabase := ExtractFileDir(OpenDialog1.FileName);
  strTableName := ExtractFileName(OpenDialog1.FileName);
  if Table1.Active then
    begin
      if Table1.State in [dsInsert, dsEdit] then
        Table1.Post;
      Table1.Close;
    end;
  if Database1.Connected then
    Database1.Close;
  Try
    begin
      slDbParams := TStringList.Create;
      slDbParams.Add('PATH='+strDatabase);
      slDbParams.Add('DEFAULT DRIVER=PARADOX');
      Database1.Params.Clear;
      Database1.Params := slDbParams;
      Database1.Open;
      slDbParams.Free;
    end;
  except
    begin
      ShowMessage('Could not open database.');
      exit;
    end;
  End;
  Try
    begin
      Table1.DatabaseName := Database1.DatabaseName;
      Table1.TableName := strTableName;
      Table1.Open;
    end;
  except
    begin
      ShowMessage('Could not open table:' + #13#10 + strTableName);
      exit;
    end;
  End;
  mnuClose.Enabled := True;
  OpenDialog1.InitialDir := strDatabase;
  OpenDialog1.FileName := '';
end;

procedure TForm1.mnuCloseClick(Sender: TObject);
begin
  Table1.Close;
  mnuClose.Enabled := False;
end;

procedure TForm1.mnuExitClick(Sender: TObject);
begin
  Form1.Close;
end;

procedure TForm1.mnuAboutClick(Sender: TObject);
var
  strMsg: string;
begin
  strMsg := 'Experimental Paradox Application.';
  strMsg := strMsg + #13#10 + 'Compiled with Delphi 7 on Windows XP';
  strMsg := strMsg + #13#10 + '2019-08-31, Niels Knabe';
  MessageDlg(strMsg,mtInformation,[mbOK],0);
end;

end.