Think your smart enough - HELP!

[Madboy]

Ok, im making my first ever address book, and in Delphi 7. I have the following code:

unit Details;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, Buttons;

type
  TfrmDetails = class(TForm)
    txtName: TEdit;
    lblName: TLabel;
    txtDateOfBirth: TEdit;
    lblDateOfBirth: TLabel;
    txtAddress: TMemo;
    lblAddress: TLabel;
    lblHomeNumber: TLabel;
    txtHomeNumber: TEdit;
    txtMobileNumber: TEdit;
    lblMobileNumber: TLabel;
    txtEmailAddress: TEdit;
    lblAIMContact: TLabel;
    txtNotes: TMemo;
    lblNotes: TLabel;
    cmdCancel: TBitBtn;
    cmdOK: TBitBtn;
    Procedure AddEntry(Fn,Ad,HP,M,E,N:string);
    procedure cmdCancelClick(Sender: TObject);
    procedure cmdOKClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  frmDetails: TfrmDetails;
  Rgn:THandle;


implementation

uses Main;

{$R *.dfm}

Procedure TfrmDetails.AddEntry(Fn,Ad,HP,M,E,N:string);
begin
     if Not fileExists(QFileName) then rewrite(QFile)
     else if Not Edit then begin
          i:=Fsize;
     end
     else begin
          frmMain.cboNameList.Items.Delete(i);
          i:=Found;
     end;
     seek(QFile,i);
     with Entries do begin
          FullName:=Fn;
          Address:=ad;
          Hphone:=hp;
          Mobile:=m;
          Email:=E;
          Note:=N;
          write(QFile,Entries);
     end;
     closefile(QFile);
     reset(QFile);
     fsize:=filesize(QFile);
     frmMain.cboNameList.Items.add(txtName.text);
     i:=frmMain.cboNameList.Items.IndexOf(txtName.text);
     frmMain.cboNameList.ItemIndex:=i;
end;

procedure TfrmDetails.cmdCancelClick(Sender: TObject);
begin
  Close;
end;

procedure TfrmDetails.cmdOKClick(Sender: TObject);
var n:integer;
begin
     if Not Edit then begin
        for n:=0 to frmMain.cboNameList.Items.count-1 do begin
            if txtName.text=frmMain.cboNameList.Items[n] then begin
               MessageBox(handle,'The name already exists! Type a different name.',
               'Name Exists',MB_Ok);
               exit;
            end;
        end;
     end;
     AddEntry(txtName.text,txtAddress.text,txtHomeNumber.text,txtMobileNumber.text,txtEmailAddress.text,txtNotes.text);
     frmMain.seekRecord;
     if Rgn<>0 then DeleteObject(Rgn);
     frmDetails.Close;
     frmDetails.Release;
end;

end.

But when i click my OK button, it errors. DOnt know the problem, anyone care to assist?

[visualAd]

As you have provided no details of the error I am stabbing in the dark.

Arn't you supposed to use the assign procedure to associate the variable QFile with the file location before using any other file I/O functions? Plus if the file does exist you don't even open it.

     Assign (QFile, QFileName);

     if Not fileExists(QFileName) then rewrite(QFile)
     else if Not Edit then begin
          Append (QFile);
          i:=Fsize;
     end
     else begin
          frmMain.cboNameList.Items.Delete(i);
          i:=Found;
     end;

[Madboy]

Thanks for that, ill test it tomorrow. I dont even know how to intercept the error messages in Delphi yet

[Madboy]

Ok, i did a check now to find out whether the file exists in APP.Path, and if it doesnt to prompt the user to create the file:

unit Main;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, ToolWin, StdCtrls, Menus, ImgList, mmsystem, ShellApi,
  Mask;

type
  TfrmMain = class(TForm)
    procedure mnuFileNewContactClick(Sender: TObject);
    procedure mnuFileEditContactClick(Sender: TObject);
    Procedure SeekRecord;
    procedure mnuFileDeleteContactClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

type
    QRecord = record
    FullName:string[40];
    Address:string[150];
    DateOfBirth:string[40];
    Hphone,Mobile:string[20];
    Email:string[50];
    Note:string[100];
end;

var
  frmMain: TfrmMain;
  Entries: QRecord;
  QFile, TempFile: File of QRecord;
  i,FSize, Found:integer;
  Deleted, Edit:boolean;
  QFileName,TempFileName: string;

implementation

uses Details;

{$R *.dfm}

Procedure TfrmMain.SeekRecord;
var n:Integer;
begin
     for n:=0 to frmMain.cboNameList.Items.count-1 do begin
         seek(Qfile,n);
         Read(QFile,Entries);
         if entries.FullName=frmMain.cboNameList.Items[cboNameList.ItemIndex] then begin
            with Entries do begin
                 with frmMain do begin
                      txtAddress.text:=Address;
                      txtHomeNumber.Text:=Hphone;
                      txtMobileNumber.Text:=Mobile;
                      txtEmailAddress.Text:=Email;
                      txtNotes.Text:=Note;
                      cboNameList.ItemIndex:=i;
                 end;
                 Found:=n;
                 break;
            end;

         end;
     end;
end;


procedure TfrmMain.mnuFileNewContactClick(Sender: TObject);
begin
  frmDetails.Caption:= 'Add new contact';
  frmDetails.ShowModal;
end;

procedure TfrmMain.mnuFileEditContactClick(Sender: TObject);
begin
  frmDetails.Caption:= 'Edit contact';
  frmDetails.ShowModal;
end;

procedure TfrmMain.mnuFileDeleteContactClick(Sender: TObject);
begin
  if cboNameList.Text = 'No contacts in address book' then
    ShowMessage('There is no contact to delete from Address Book')
  else
    //
end;

procedure TfrmMain.FormCreate(Sender: TObject);
var n:integer;
begin

     TempFileName:=ExtractFilePath(application.exename)+'RecTemp.dat';
     AssignFile(TempFile,TempFileName);
     if FileExists(TempFileName) then Erase(TempFile);

     QFileName:=ExtractFilePath(application.exename)+'Records.dat';
     Assignfile(QFile, QFileName);
     if FileExists(QfileName) then begin
        reset(QFile);
        FSize:=FileSize(QFile);
        if FSize>0 then begin
           for n:=0 to Fsize-1 do
           begin
                seek(Qfile,n);
                Read(QFile,Entries);
                cboNameList.Items.add(Entries.FullName);
           end;
           cboNameList.ItemIndex:=0;
           SeekRecord;
        end
     end
     else begin
          if Application.MessageBox('Address Book requires new data file in order to save contacts'+#13#10+#13#10+'Would you like to save it now?',
             'Address Book', MB_YesNo)=IDyes then begin
             ReWrite(QFile);
             Reset(QFile);
             i:=0;
          end;
     end;
     i:=0;
end;

Which works perfect, now when i click File > New contact from me menu, fill in required details, and click OK it works great too. Only problem is, when i close my app, and rerun it, it errors again:

[CORONA BEER]

I dont know really unless i make the app myself cuz i'm just begining Delphi also but would this help?
//---
Assignfile(QFile, QFileName);
if FileExists(QfileName) then begin
reset(QFile);
IF IOResult >0 THEN BEGIN
for n:=0 to Fsize-1 do
//---

[Madboy]

Ill try in a bit thanks,

by the way, how do you block errors? In VB its like:

On Error Resume Next

or

On Error Goto Label

Dont know how to block them in Delphi

CHeers

[CORONA BEER]

I think Delphi blocks errors by using Try

Begin
Try
Finally
end;

begin
try
except
on E: Exception do ErrorDialog(E.Message, E.HelpContext);
end;

[visualAd]

In pascal you use compiler directives to turn error handling on and off.

{$I-} - Turns off file IO error checking for example.

and

{$I+} - Turns it back on.

So you can do somethng like this:

AssignFile (F, FPath);

{$I-}
ReWrite (F);
{$I+}

If IOResult = 0 then
  (* file created successfully *)
Else
  (* file not created *)

This might be slightly different in Delphi though.

[Madboy]

Cheers for the tips n that dudes, will experiment now....after i get a beer chilled from the fridge

PS: Corona, if im writing a messagebox, with a normal caption, how do iget the string in the middile?

ShowMessage('There are' + S + ' contacts available in the Address Book)

[CORONA BEER]

ShowMessage('There are '+ S +' contacts available in the Address Book')

use the
{$I-} - Turns off file IO error checking for example.

and

{$I+} - Turns it back on.

like visualAd said i forgot bout thT.

[Madboy]

Cheers VisualAd, Corona

Last problem, i hope How do you count the number of items in a Combobox? I have:

procedure TfrmMain.mnuViewStatisticsClick(Sender: TObject);
var
S:String;
i:Integer;
begin

For I:=0 To cboNameList.Items.Count - 1 do
S:= S + cboNameList.Items.Text[i] + ' ';
ShowMessage('There are '+ S +' contacts available in the Address Book')
end;

end.

But that just shows the text in the combo box, not the amount of items

[Madboy]

Oh, and incase you think the problems were solved, they wernt

[Madboy]

OK

I have now sucesfully got a working array
I can now add new contacts, delete them and show them when i load my program up. There is one problem though, in which if i add a new contact, then click File > New again, it errors. I dont know why it errors (maybe i need to close the file, if so how?). If thats not the problem, maybe i can shove an error handle in there somewhere.

See that? I would never of come close to making something like this in VB, Delphi seems to take p**s out of VB, hahahaha.

So ill try that method, first though, how do you close a file? The reason i ask is, i mentioned that i can create a new contact with no problems, but trying to add a new one straight after errors. Well if i add a contact, close the program then re-open, i can add a contact with no problems. So i must be getting an overflow error trying to write to the file whilst it is already open, thats my theory anyway.

Any other suggestions appreciated

EDIT: Those error handles stated above, thats just for IO operations right? I only want to know how to do a simlilar thing to On Error Resume Next , nothing else, forget the files part, this is a question irrelated to IO

[CORONA BEER]

//---
Assignfile(QFile, QFileName);
if FileExists(QfileName) then begin
reset(QFile);
FSize:=FileSize(QFile);
if FSize>0 then begin
for n:=0 to Fsize-1 do
begin
seek(Qfile,n);
Read(QFile,Entries);
cboNameList.Items.add(Entries.FullName);
end;
cboNameList.ItemIndex:=0;
SeekRecord;
CloseFile(QFile); // added this
end
end
else begin
//---

[Madboy]

that eliminates one problem, but creates another.

Before if i tried to add a new contact, then another it errored as soon as i clicked File > New. Now this doesnt happen, it shows my form to add the new contact, but when i click OK it errors, maybe i need to open the file when the form loads? If not im confused

Cheers

[Madboy]

All sorted, hahaha. First program in Delphi done, took a day. Would of took a month in VB, and its complete, the Address Book.

Cheers everyone, well VisualAd, Corona

Still didnt get the error handling to work, but ill find it out soon