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Home » Newsletter » September 2007

By R. Vyshakh and D. Ashwini

For this month's article on eDocEngine VCL, we will see how to load a list of mail-merge variables from a CSV (comma-separated values) file and then dynamically write them to documents at run time. The source code presented here will use the PDF engine (TgtPDFEngine).

First, you create a string list and load the values from the CSV.

CurrRec: Integer;
CustomerList: TStringList;

...
// Load mail-merge variables from a CSV into a list
CustomerList := TStringList.Create;
...
CustomerList.LoadFromFile('CustomerList.csv');

To ensure that custom placeholders in strings are translated at run-time, you need to set the TgtPDFEngine.Preferences.CalculateVariables property to true. You can then text out strings with custom variables. You need to mark the placeholders with the delimiters <% and %>.

with gtPDFEngine1 do
begin
 ...
 // Enable translation of custom placeholders
 Preferences.CalculateVariables := True;
 ...

 for LI := 0 to CustomerList.Count - 1 do
 begin
   BeginDoc;
   TextOut(0, 0.25, 'Date: ');
   TextOut(0.75, 0.25, CphShortDate );

   TextOut(0, 0.5, 'Address:');
   // Write strings with custom placeholders
   TextOut(0.75, 0.5, '<%CustomerAddress%>');

   TextOut(0, 1.25, 'Dear <%CustomerName%>,');

   TextOut(0, 0.75, 'E-Mail:');
   TextOut(0.75, 0.75, '<%CustomerE-mail%>');
   ...
   EndDoc;
   CurrRec := LI;
 end;
end;

Next, you need to handle the OnCalcVariables event of the PDF engine so that at run-time you are able to supply the mail-merge variables from the string list.

procedure TForm1.gtPDFEngine1CalcVariables(
    Sender: TgtCustomDocumentEngine;
    Variable: String; var Value: String);
var
  LTemp: TStringList;
begin
  LTemp := TStringList.Create;
  try
    LTemp.CommaText := CustomerList[CurrRec];
    // Provide relevant values from the string list 
    // for custom placeholders 
    if Variable = 'CustomerName' then
      Value := LTemp[0]
    else if  Variable = 'CustomerAddress' then
      Value := LTemp[1]
    else if Variable = 'CustomerE-mail' then
      Value := LTemp[2];
  finally
    LTemp.Free;
  end;
end;

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Downloads:

• Zipped project file plus executable and sample CSV.