How to use a function outside FR in a report

Comments

• gordk St.Catherines On. Canada.

  January 2004 edited 7:35AM

  Hi Ingo
  
  Since Fr is limited to the functions available in the expression editor
  a userfunction is provided to work with external library functions.
  the on user function of fast report
  This function can pass up to 3 paramaters out of the report and return
  1 variant value. When Fr encounters an uknown function name in it's script
  it fires the onuserfunction event.
  sample use would be myvarname :=[myfunctioname(p1,p2,p3)];
  example of report script in an on before print event of a band.
  myvarname :=[MONEYTOSTR([varaible/fieldname])];
  
  clicking on the onuserfunction event of the Tfrreport component will
  bring up delphi's code editor.
  
  
  procedure TForm1.frReport1UserFunction(const Name: String; p1, p2, p3: Variant; var Val: Variant);
  begin
  
  end;
  
  First we must declare variables of the correct type to hold the values
  which will be passed out in the parameters
  p1,p2,p3.
  our code now looks like this. for this example we will only pass one paramater
  
  procedure TForm1.frReport1UserFunction(const Name: String; p1, p2, p3: Variant; var Val: Variant);
  var
  
  d1: Double;
  d2 : what ever type required; // if passing more parameters
  d3 : what ever type required;
  begin
  
  if name <> 'MONEYTOSTR' then Exit; //if name does not match get out
  d1 := frParser.Calc(p1); // get value from report and store in variable "d1"
  val := MyMoneyToStr(d1); // modify the value in d1 with an external Delphi library function
  // and return it to the report in value.
  end;
  
  Now myvarname in the report will contain the textstring.
  So any time any report, handled by frreport1 encounters the
  function MONEYTOSTR([varaible/fieldname]); internally
  it will jump out to Delphi and do what is required.
  
  a little better way to write this would be
  begin
  if AnsiCompareText(Name, 'MONEYTOSTR') = 0 then
  begin
  d1 := frparser.calc(p1);
  val := MyMoneyToStr(d1);
  end;
  //....... place as many other functions here as needed.
  
  
  end;
  if you don't want this function available then before you load a report
  into the report component set the onuserfunction to nil.
  regards
• ibalzer

  January 2004 edited 7:35AM

  Thanks,
  
  it works.
  I had seen, that the function not works, when it is a function without parameters, e.g.
  
  function Checkit: boolean;
  begin
  // check the value
  end;
  
  and OnbeforePrint:
  ....
  if AnsiCompareText('CheckIt', Name) = 0 then
  begin
  val:= CheckIt;
  end;
  
  FR fires a Exception 'unknown symbol CHECKIT'
  It is correct?
  
  Regards, Ingo