printer error trap

[xenblaise]

I am using that code to print a memo, however if I have no printer installed, it errors, how can I trap the error? so that, it will not crash the program.

procedure PrintTStrings(Lst : TStrings) ;
var
  I,
  Line : Integer;
begin
  I := 0;
  Line := 0 ;
  Printer.BeginDoc;
  for I := 0 to Lst.Count - 1 do begin
    Printer.Canvas.TextOut(0, Line, Lst);
    Line := Line + Abs(Printer.Canvas.Font.Height);
    if (Line >= Printer.PageHeight) then
      Printer.NewPage;
  end;
  Printer.EndDoc;
end;

procedure TForm1.BTNprintClick(Sender: TObject);
begin
if Printer.Printers.Strings[-1]<>'' then
begin

try
PrintTStrings(Memo1.lines);
except
showmessage('NO printer');
end;

end;

end;


using that code because assignprn() is gone.

[mas steindorff]

if you drop a printer dialog on your form and test it's result, you can skip the printout

Code: [Select]

if not printdialog1.execute then
  exit;
there are other dialogs you can chose from if this one does not do the "scan for printers" operation your after.

[xenblaise]

very good answer,

Ok;

do you have any idea how would i print my dbgrid datas to a printer?


thanks

[mas steindorff]

very good answer,

do you have any idea how would i print my dbgrid datas to a printer?

you should be able to use your existing code.  does it work normally when you have a printer? 
when I convert arrays and grids to strings, I like to use a TStringList.  that way I can convert number at a time.
 loop for each value in the grid...
 sline := sline +format('%3.5f,',[value1]);
 loopend
and then add the line to the tstring list
Tstr.add(sline);
later I can step the TString as a line per index

Code: [Select]

if printDialog1.execute then begin
       PrintTStrings(Memo1.lines);
    end else begin
       showmessage('NO printer selected');
    end;


[xenblaise]

Thanks

I got that.