Error with Template file

rbuser

I am doing the following...
When user hits Print Preview i look to see if the Template file exists and
if so then set the Template.FileName to that file and then call
Template.LoadFromFile
This then loads the Template which i originally made in design time.
I want to be able to just drop in another file and that Template to load if
the user requires a different layout of the Report.

I created a Blank report with just a Shape on it and loaded that file, but
after the call to Template.LoadFromFile i get the error box saying

Error reading ppReport1.OnPreviewFormCreate : Invalid property value. Ignore
the error and continue.

If i press ignore then the new Report with the Shape does load up but i
don't want this error box coming up each time the user puts in a new
Template file.
What am i doing wrong please ?

BTW The original report gets it data from a DBPipeline and i do not have any
code in the OnPreviewFormCreate event. In fact i do not have any code in any
of the events.
I am using Delphi5 Enterprise and Report Builder Version 6.02

Thanks
John

rbuser

Hi John,

register your own dialog.
I don't show the dialog, but write the unknown property/method into a log
file, that my human report designer knows - Ah, here's a report I should
open and save.

here some code from my main datamodule :


ppUnRegisterForm(TppCustomTemplateErrorDialog);
ppRegisterForm(TppCustomTemplateErrorDialog, TdlgTemplateErrorDialog);


and here the code for the dialog :


unit UdlgTemplateErrorDialog;

interface

uses
Windows,
Messages,
SysUtils,
Classes,
Graphics,
Controls,
Forms,
Dialogs,
ppForms,
ppTypes,
ppUtils,
StdCtrls,
ExtCtrls;

type
TdlgTemplateErrorDialog = class(TppCustomTemplateErrorDialog)
pnlMain: TPanel;
pnlBottom: TPanel;
memErrorMessage: TMemo;
procedure FormShow(Sender: TObject);
procedure FormClose(Sender: TObject; var Action: TCloseAction);
procedure FormCreate(Sender: TObject);
private
{ Private-Deklarationen }
protected
function GetErrorMessage : String; override;
procedure SetErrorMessage(pmMessage : String); override;
public
{ Public-Deklarationen }
end;

var
dlgTemplateErrorDialog: TdlgTemplateErrorDialog;

implementation

{$R *.DFM}

uses
ppReport;

procedure TdlgTemplateErrorDialog.FormShow(Sender: TObject);
begin
PostMessage(Handle, WM_CLOSE, 0, 0);
end;

function TdlgTemplateErrorDialog.GetErrorMessage : String;
begin
Result := memErrorMessage.Text;
end;

procedure TdlgTemplateErrorDialog.SetErrorMessage(pmMessage : String);
var
af : TForm;
msg : String;
fn : String;
ms : TMemoryStream;
begin
memErrorMessage.Text := pmMessage;

// log this message
try
fn := ExtractFilePath(Application.ExeName) + 'event.report.log';
ms := TMemoryStream.Create;
try
if FileExists(fn) then begin
ms.LoadFromFile(fn);
end;
ms.Seek(0, soFromEnd);

msg := DateTimeToStr(Now) + ' : ' + pmMessage + #13#10;

af := Screen.ActiveForm;

// proprietary code here
[...].

msg := msg + '----------------------------------' + #13#10;

ms.Write(msg[1], Length(msg));

ms.SaveToFile(fn);
finally
ms.Free;
end;
except
on E : Exception do begin
end;
end; // try/except
end;

procedure TdlgTemplateErrorDialog.FormClose(Sender: TObject;
var Action: TCloseAction);
begin
ModalResult := mrAll;
end;

procedure TdlgTemplateErrorDialog.FormCreate(Sender: TObject);
begin
// no flicker, this form is a dummy and really shown!
Left := Screen.Width;
end;

end.


regards,
Chris Ueberall;

rbuser

Thanks for this helpful code Chris (which i will use ;-), but i would really
like to know why i get the error in the first place.
Perhaps i should have mentioned that i am quite new to programming, but i
think what you are saying is to only write the error to a file and not show
the error box.
As i said though,i would also like to know why i get the error in the first
place.

Thanks
John

rbuser

Hi John,

Your template has a assigned event methode. You will see that when you open
the RTM as text file, asuming you used pure ASCII as storage format. it is
just like opening a form (DFM) in delphi which had assigned the 'FormCreate'
methode, but was removed from the PAS file.

regards,
Chris Ueberall;

digitalmetaphors

Chris is right, the delphi streaming logic attempts to find this event
handler, but when none exists on your form unit, then it says that it can't
find a method for method pointer that it is trying to create and assign.
There is also a tech tip article which describes how you can lose an event
handler in the Templates thread of the TechTips newgroup.


Cheers,

Jim Bennett
Digital Metaphors

rbuser

I see, thanks to you both for the help
John