Iterating a dataset in an OnCalc event

rbuser

Hi,

I want to loop through all values in a RAP dataset linked to the main
dataset and populate the result with all recoords of a specific field,
in this case telephone numbers. RAP seems to know about EOF but it
roesn't recognise Next. So how can I do this.

Or is there another way without even using RAP.

Thanks,

Ken

rbuser

On 18/11/2015 12:21, Ken Randall wrote:

I wrote my own RAP class for this:

//MMWIN:CLASSCOPY
unit _MM_Copy_Buffer_;

interface

type
TnavTppDataPipelineRTTI = class(TraTppDBPipelineRTTI)
public
class procedure GetPropList(aClass : TClass; aPropList : TraPropList);
override;
class function GetPropRec(aClass : TClass; const aPropName : String;
var aPropRec : TraPropRec) : Boolean; override;
class function GetParams(const aMethodName : String) : TraParamList;
override;
class function CallMethod(aObject : TObject; const aMethodName :
String; aParams : TraParamList; aGet : Boolean) : Boolean; override;
class function GetPropValue(aObject : TObject; const aPropName :
String; var aValue) : Boolean; override;
class function RefClass : TClass; override;
class function SetPropValue(aObject : TObject; const aPropName :
String; var aValue) : Boolean; override;
end;


implementation


{ TnavTppDataPipelineRTTI }

class function TnavTppDataPipelineRTTI.CallMethod(aObject : TObject;
const aMethodName : String; aParams : TraParamList; aGet : Boolean) :
Boolean;
var
lPipeline : TppDBPipeline;
begin

Result := True;

lPipeline := TppDBPipeline(aObject);

if ppEqual(aMethodName, 'First') then
begin
TppDataPipelineAccess(lPipeline).First;
end
else
if ppEqual(aMethodName, 'Last') then
begin
lPipeline.Last;
end
else
if ppEqual(aMethodName, 'Next') then
begin
TppDataPipelineAccess(lPipeline).TraverseBy(1);
end
else
if ppEqual(aMethodName, 'Prior') then
begin
TppDataPipelineAccess(lPipeline).TraverseBy(-1);
end
else

Result := inherited CallMethod(aObject, aMethodName, aParams, aGet);
end;

class function TnavTppDataPipelineRTTI.GetParams(const aMethodName :
String) : TraParamList;
begin
Result := inherited GetParams(aMethodName);
end;

class procedure TnavTppDataPipelineRTTI.GetPropList(aClass : TClass;
aPropList : TraPropList);
begin
inherited GetPropList(aClass, aPropList);

{add methods}
aPropList.AddMethod('First');
aPropList.AddMethod('Last');
aPropList.AddMethod('Next');
aPropList.AddMethod('Prior');
end;

class function TnavTppDataPipelineRTTI.GetPropRec(aClass : TClass; const
aPropName : String; var aPropRec : TraPropRec) : Boolean;
begin
Result := True;

if ppEqual(aPropName, 'First') then
MethodToRec(aPropName, False, aPropRec) else
if ppEqual(aPropName, 'Last') then
MethodToRec(aPropName, False, aPropRec) else
if ppEqual(aPropName, 'Next') then
MethodToRec(aPropName, False, aPropRec) else
if ppEqual(aPropName, 'Prior') then
MethodToRec(aPropName, False, aPropRec) else
Result := inherited GetPropRec(aClass, aPropName, aPropRec);
end;

class function TnavTppDataPipelineRTTI.GetPropValue(aObject : TObject;
const aPropName : String; var aValue) : Boolean;
begin
Result := inherited GetPropValue(aObject, aPropName, aValue);
end;

class function TnavTppDataPipelineRTTI.RefClass : TClass;
begin
Result := inherited RefClass;
end;

class function TnavTppDataPipelineRTTI.SetPropValue(aObject : TObject;
const aPropName : String; var aValue) : Boolean;
begin
Result := inherited SetPropValue(aObject, aPropName, aValue);
end;

initialization
raUnregisterRTTI(TraTppDBPipelineRTTI);
raRegisterRTTI(TnavTppDataPipelineRTTI);

finalization

raUnregisterRTTI(TraTppDBPipelineRTTI);
raRegisterRTTI(TnavTppDataPipelineRTTI);


end.

nicocizik

Hi Ken,

The solution Paul gave is a great example of extending the RAP RTTI.

It is also possible to create a RAP pass-thru function to perform the
same task. You could create a pass-thru function named
PipelineNext(aPipeline), which takes the DataPipeline as a parameter and
then calls .Next in Delphi. See the RAP demos for examples of pass-thru
functions.

I'm however a bit unclear about what you are trying to accomplish. Do
you wish to populate a TppVariable with all the phone numbers in the
dataset? If you would like to display all records in a field, why not
just connect that dataset to a subreport and have it iterate through the
dataset for you?

rbuser

Thanks, Nico,

That is what I have now done.

Ken

rbuser

Thanks Paul.

rbuser

On 18/11/2015 15:15, Nico Cizik (Digital Metaphors) wrote:

Yes, I created my RAP RTTI class because I wanted to get info and store
it in a structure BEFORE the report prints so that I could make
decisions about whether to display groups etc in advance.

rbuser

The problem with using a subreport is that when report is exported to
Excel the contents of the subreport are not included. My subreport is a
child report. Is there a way to do this?

nardmoseley

Hi Ken,

For XlsReport all elements are exported.

For XlsData the default behavior is main report detail elements are
exported. Use the File | Print To File Setup dialog to specify which bands
and component to export. For a subreport, access the workspace for the
childreport and use the File | Print To File Setup dialog from there.

Check out the RBuilder Help topics for TppXlsReportDevice and
TppXlsDataDevice for more details on using these devices.




Best regards,

-
Nard Moseley
Digital Metaphors
www.digital-metaphors.com