Call Delphi function From RAP

rbuser

Hi

how i can call Delphi function from RAP and assigned the Result value to
Variable

for example

i have Delphi function

function GetZipCode(const City, St, StNum: string): string
begin
...
end;



how to call this function From RAP ???

Thanks

digitalmetaphors

RAP has a pass through function capability. Basically, it is a class that is
compiled and then it allows you to make a call in RAP that calls your new
class code which makes the Delphi method call. There are tutorials and
examples in the RAP help file and also in the developer's guide pdf and in
the RBuilder\Demos\RAP folder. The parameters are also able to be handled.
Here is a RAP pass through function that takes a TppReport object as a
parameter and returns the top margin in microns.

type
TdmTopMarginInMicrons = class(TraSystemFunction)
public
class function Category: String; override;
class function GetSignature: String; override;
class function HasParams: Boolean; override;

procedure ExecuteFunction(aParams: TraParamList); override;
end;

implementation

{Top}

class function TdmTopMarginInMicrons.Category: String;
begin
Result := 'DrawCommandMeasurements';
end;

procedure TdmTopMarginInMicrons.ExecuteFunction(aParams: TraParamList);
var
lReport: TppReport;
liMargin: Integer;
begin

GetParamValue(0, lReport);

liMargin := lReport.PrinterSetup.PageDef.mmMarginTop;

SetParamValue(1, liMargin);

end;

class function TdmTopMarginInMicrons.GetSignature: String;
begin
Result := 'function TopMarginInMicrons(Report: TppReport): Integer;';
end;

class function TdmTopMarginInMicrons.HasParams: Boolean;
begin
Result := True;
end;

initialization
raRegisterFunction('TopMarginInMicrons', TdmTopMarginInMicrons);

finalization
raUnRegisterFunction('TopMarginInMicrons');


Cheers,

Jim Bennett
Digital Metaphors

rbuser

Thanks
i have more 1 question...

i can add my custom function to the report only at runtime (with the
Designer Component) ?
because when the application is in design time the function is not
registered (initialization Section)

digitalmetaphors

You'll have to compile the RAP pass through functions into the app. The only
way to make this dynamic so you wouldn't have to recompile the app everytime
you wanted to add pass through functions would be to add a hot swapable
package architecture. The packages would include the pass through function
classes and registration calls. Delphi can do this and there are usually
topics like this out on the web. I remember Mark Miller put on a good show
about this topic at BorCon (Long Beach, Ca. IIRC) a couple of years ago
called Building Dynamic Applications.


Cheers,

Jim Bennett
Digital Metaphors