Newbie: Setting connection params at runtime

rbuser

Hi,

I would like to do the following:

Have one app and one tPPReport and reuse it for:

Loading different rtm files, and supplying different database parameters at
run time.
I can load the rtm files, but I am stuck trying to find how I populate the
database connection parameters. I will also probably want to pass parameters
programatically too...

Can't seem to find the info in the help. It might help if I say that I`m
trying to include rtm files for reporting from a cgi application.

Can someone fasttrack me to some help?

tia

digitalmetaphors

You can store the name of the database as well as the parameters with each
template. That way, when you load the template you can access that data and
know which database to connect to and which parameters to pass to the
database object to configure it. See the information below on storing custom
information in a template.

--
Cheers,

Alexander Kramnik
Digital Metaphors


-----------------------------------------------------
Tech Tip: Storing Custom Information with Templates
-----------------------------------------------------

Question:
---------

How can I store descriptive information with my report template?


Solution:
---------

1. If you are storing the templates to a database, then you can use the
Report.Template.OnSaveEnd and OnLoadEnd events to store and load the
custom information to appropriate data fields for the record. (This is
the technique used by the ReportExplorer.)

2. If you are storing templates to .rtm files, then you will need to
store the custom information in an Offset area of the template file. The
Report.Template object enables you do this by utilizing the
Template.Offset property and the Template.OnLoadStart and OnLoadEnd
events. Below is a detailed example.



Example:
--------
- Create a new application.
- Add to the main form one TButton, one TppReport and one TppDesigner.

- Set the Designer's Report property to ppReport1.
- Add ppTypes to the uses clause.


type
TForm1 = class(TForm)
Button1: TButton;
ppReport1: TppReport;
ppDesigner1: TppDesigner;
procedure FormCreate(Sender: TObject);
procedure Button1Click(Sender: TObject);
private
procedure LoadReportStreamEvent(Sender: TObject; Stream: TStream);
procedure SaveReportStreamEvent(Sender: TObject; Stream: TStream);

public

end; { class TForm1 }


{note: use compiler directive to declare strings as 'ShortStrings'
this is required for record structures}

{$H-}

{record structure used to store information inside report template }
TmyTemplateInfo = record
HeaderID: Integer;
Comments: String;
DateTime: TDateTime;

end; {record, TppTemplateRec}

{$H+}


const
cHeaderID = 12345;

implementation


{-------------------------------------------------}
{ TForm1.FormCreate }

procedure TForm1.FormCreate(Sender: TObject);
begin

{setup Template events }
ppReport1.Template.Format := ftASCII;
ppReport1.Template.Offset := SizeOf(TmyTemplateInfo);
ppReport1.Template.OnLoadStart := LoadReportStreamEvent;
ppReport1.Template.OnSaveEnd := SaveReportStreamEvent;

end; {procedure, FormCreate}

{-------------------------------------------------}
{ TForm1.Button1Click }

procedure TForm1.Button1Click(Sender: TObject);
begin

ppDesigner1.Show;

end; {procedure, Button1Click}

{--------------------------------------------------}
{ TForm1.LoadReportStreamEvent }

procedure TForm1.LoadReportStreamEvent(Sender: TObject; Stream:
TStream);
var
lTemplateInfo: TmyTemplateInfo;
lsMessage: String;

begin

{read string stored in template header }
Stream.Seek(0, soFromBeginning);
Stream.Read(lTemplateInfo, SizeOf(TmyTemplateInfo));

{note: if not one of the templates with our header info, then set
Offset to 0 }
if lTemplateInfo.HeaderID = cHeaderID then
begin
lsMessage := 'Reading data from template file: ' + #13#10 + #13#10
+
lTemplateInfo.Comments + ' (' +
DateTimeToStr(lTemplateInfo.DateTime) + ')';

MessageDlg(lsMessage, mtInformation, [mbOK],0);
ppReport1.Template.Offset := SizeOf(TmyTemplateInfo);
end
else
ppReport1.Template.Offset := 0;

end; {procedure, LoadReportStreamEvent}


{-----------------------------------------------------------------------
-------}
{ TForm1.SaveReportStreamEvent }

procedure TForm1.SaveReportStreamEvent(Sender: TObject; Stream:
TStream);
var
lTemplateInfo: TmyTemplateInfo;
lsMessage: String;

begin

lTemplateInfo.HeaderID := cHeaderID;
lTemplateInfo.Comments := 'This comment is being stored inside the
report template, ' + #13#10 +
'along with the date and time written. ';
lTemplateInfo.DateTime := Now;

{write info to template header}
Stream.Seek(0, soFromBeginning);
Stream.Write(lTemplateInfo, SizeOf(TmyTemplateInfo));

lsMessage := 'Writing data to template file: ' + #13#10 + #13#10 +
lTemplateInfo.Comments + ' (' +
DateTimeToStr(lTemplateInfo.DateTime) + ')';
MessageDlg(lsMessage, mtInformation, [mbOK],0);

end; {procedure, SaveReportStreamEvent}