Invoicing in Delphi: Show Me the Money

Below is the listing for the entire main unit:

unit invmain;

interface

uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics,
  Controls, Forms, Dialogs, Buttons, StdCtrls, RpDefine, RpCon,
  RpConDS, DB, ADODB, Grids, DBGrids, RpRave, Menus, ExtCtrls,
  ToolWin, ComCtrls,math, INIFiles, RpRender, RpRenderPDF,
  RpRenderRTF, RpRenderHTML;

type 
  TForm1 = class(TForm) 
    MainMenu1: TMainMenu; 
    PopupMenu1: TPopupMenu; 
    File1: TMenuItem; 
    Windows1: TMenuItem; 
    Clients1: TMenuItem; 
    ools1: TMenuItem; 
    Settings1: TMenuItem; 
    ViewAllClients1: TMenuItem; 
    About1: TMenuItem; 
    Exit1: TMenuItem; 
    Panel1: TPanel; 
    btndelete: TBitBtn; 
    Statistics1: TMenuItem; 
    btnAddInv: TBitBtn; 
    srchpnl: TPanel; 
    rb1: TRadioButton; 
    rb2: TRadioButton; 
    edsearch: TEdit; 
    btnsearch: TBitBtn; 
    BitBtn1: TBitBtn; 
    Label1: TLabel; 
    Label2: TLabel; 
    StaticText2: TStaticText; 
    StaticText3: TStaticText; 
    db1: TDBGrid; 
    ado1: TADOTable; 
    d1: TDataSource; 
    ado1invno: TAutoIncField; 
    ado1invname: TWideStringField; 
    ado1invdate: TDateTimeField; 
    ado1notes: TMemoField; 
    ado1status: TWideStringField; 
    ado1amount: TBCDField; 
    ado1total: TBCDField; 
    procedure File1Click(Sender: TObject); 
    procedure CreateNewInvoice1Click(Sender: TObject); 
    procedure BitBtn2Click(Sender: TObject); 
    procedure db1DblClick(Sender: TObject); 
    procedure Exit1Click(Sender: TObject); 
    procedure FormCreate(Sender: TObject); 
    procedure db1CellClick(Column: TColumn); 
    procedure FormShow(Sender: TObject); 
    procedure btndeleteClick(Sender: TObject); 
    procedure btnAddInvClick(Sender: TObject); 
    procedure Statistics1Click(Sender: TObject); 
    procedure btnsearchClick(Sender: TObject); 
    procedure Settings1Click(Sender: TObject); 
    procedure ViewAllClients1Click(Sender: TObject); 
    procedure About1Click(Sender: TObject); 
    procedure BitBtn1Click(Sender: TObject); 
    procedure ado1AfterPost(DataSet: TDataSet); 
    procedure ado1AfterScroll(DataSet: TDataSet); 
   { procedure ado1AfterPost(DataSet: TDataSet); 
    procedure ado1AfterScroll(DataSet: TDataSet); }

  private 
    { Private declarations }

  public 
    { Public declarations } 
     vat:real; 
     con,rav:string; 
     num:integer; 
  end;

var 
  Form1: TForm1;

implementation

{$R *.dfm}

uses newinv,viewchange, stats, settings, viewclients, about;
procedure TForm1.File1Click(Sender: TObject);
begin
  close;
end;

procedure TForm1.CreateNewInvoice1Click(Sender: TObject);
begin
  form2.Show;
end;

procedure TForm1.BitBtn2Click(Sender: TObject);
begin
  close;
end;

procedure TForm1.db1DblClick(Sender: TObject);
begin
  //num:=db1.Fields[0].AsInteger;
  num:=ado1.RecNo;
  ado1.recno:=num;
  with TForm5.Create(Application) do
  begin 
    ShowModal; 
    Free;
  end;

  //form5.show;
end;

procedure TForm1.Exit1Click(Sender: TObject);
begin
  close;
end;

procedure TForm1.FormCreate(Sender: TObject);

var
  settings : TINIFile;

begin
  settings := TINIFile.Create(ExtractFilePath(Application.EXEName) + 'settings.ini'); 
  try
    con:=settings.ReadString('Settings', 'con',''); 
  //showmessage(con);
  vat:=settings.ReadFloat('Settings', 'vat',8.5); 
  //  showmessage(floattostr(vat));
  rav:=settings.ReadString('Settings', 'rav','');
  showmessage(rav); 
  finally 
   settings.Free; 
  end; 
  {if (ip= 'Empty') or (port<1) then begin 
    messagedlg('Your connection details are not set. Click ok to continue.', mtInformation,[mbOk], 0); 
     } 
end;

procedure TForm1.db1CellClick(Column: TColumn);
begin
  //a:='clicked';
end;

procedure TForm1.FormShow(Sender: TObject);

var
  i:integer;

begin
  //set ado properties
  ado1.ConnectionString:=con;
  ado1.TableName:='invoices';
  ado1.Active:=true;
  label1.caption:=inttostr(ado1.RecordCount); 
  i:=ado1.RecordCount;
  label2.Caption:=inttostr(i);
end;

procedure TForm1.btndeleteClick(Sender: TObject);
begin
  if ado1.RecordCount > 0 then
  begin
    ado1.Delete;
  end
  else
    showmessage('No invoices to delete');
end;

procedure TForm1.btnAddInvClick(Sender: TObject);
begin
  ado1.Active:=false;
  //form1.ado1.TableName:='';
  form2.show;
end;