ppVariable Subclass and RAP

rbuser

Hello All:

I subclassed the DBText component and over-rode the GetTheText method to
allow users to set a "Special" display format for zero value database
fields. This allows users to specify N/A for 0 or null values.


I'd like to do the same thing using ppVariables.

However, the ppVariables calculate their value using RAP. I created a
decendent variable, but overriding the GetTheText method did not work ( the
passed value is not the RAP assigned value ).

Is this possible ??? What have I done wrong below ???

Thank you


Neil Huhta

Listed below is my override of the GetTheText



function TppNHVariable.GetTheText: String;
var
lsText: String;
lsFormat: String;
lValue: Variant;
DoTraditionalFormat:Boolean;
begin


// try lValue := username
// else lvalue:=Value

lValue := GetCustomValue;


if (pppcDesigning in DesignState) and not(Printing) then
lsText := lValue

else
begin
DoTraditionalFormat:=True;
if Assigned(OnFormat) then
begin
lsFormat := '';
FOnFormatIsAssigned:=True;
end
Else
begin
lsFormat := DisplayFormat;
FOnFormatIsAssigned:=False;
end;
if ((DataType=dtCurrency) or (DataType=dtDouble) or
(DataType=dtSingle)) and
(Not(FOnFormatIsAssigned)) and
(FDisplayZeroIgnored<>True) Then
begin
if (DisplayZeroFormat <> Null) and ((lValue = NULL) or (lValue=0))
Then //(lValue=0) and
begin
lsText:=DisplayZeroFormat;
DoTraditionalFormat:=False;
end
end;
if DoTraditionalFormat=True Then
begin

lsText := ppFormat(lsFormat, FDataType, lValue);
end;
end;

if Assigned(OnFormat) then
OnFormat(Self, DisplayFormat, FDataType, lValue, lsText);

Result := lsText;

end; {function, GetTheText}

digitalmetaphors

In RAP, when are you assigning the value to the variable?

Cheers,

Jim Bennett
Digital Metaphors

rbuser

Jim:

I am assigning it in the Calc tab of the designer. I thought that took
the place of the OnCalc event.

What do I need to do to create a successful subclass ???

I thought that the value of the ppVariable was passed from function
"GetCustomValue" in procedure "GetTheText"

Unfortunately, GetCustomValue is a private function so I cant get access
to it.

Can you help me on this ???


Neil Huhta

digitalmetaphors

It may be that the value is being restored from the cache in the report
engine. We'll have to dig into a test project to find out. Can you send
your descendent as a starting point for us? It may or may not be a simple
fix but we can look at it. Please send it to support@digital-metaphors.com


Cheers,

Jim Bennett
Digital Metaphors