Currency Formatting with Delphi -

i trying writte code in delphi, displaying given number in currency format this:

now works if filled whole number , field until paramater updated. i'd happy have code displaying number in currency format writte it. i've tried manage typing this:

procedure tform1.editzakladchange(sender: tobject); var zaklad: currency; begin   zaklad := strtofloat(editzaklad.text);   editzaklad.text := floattostrf(zaklad, ffcurrency, 10, 2); end;  end. 

but everytime when someting typed in (zaklad field), error appears:

could me that, please?

make sure maxlength of edtzaklad 0.

var   form21: tform21;   check:string; //to break loop.  function getcurrency(num: string):string; var   i: integer ;   str:string;   zaklad: currency; begin   result := '';   := 1 length(num)   begin     if (num[i] in ['0'..'9'])     begin       str := str + num[i] ;       zaklad := strtofloat(str);       result := floattostrf(zaklad, ffcurrency, 10, 2);       check := result;     end;   end; end;  function extractcurrencysymbol(zaklad: string):string; var   i: integer ;   str:string; begin   result := '';   := 1 length(zaklad)   begin     if not (zaklad[i] in ['0'..'9','.',','])     begin       str := str + zaklad[i];       result := ' '+trim(str);   end;   end;  end;  procedure tform21.editzakladchange(sender: tobject); begin   if ansipos(check,editzaklad.text) <> 0 exit;   if (trim(editzaklad.text) = '') exit   else   begin     editzaklad.text := getcurrency(editzaklad.text)+extractcurrencysymbol(editzaklad.text);     exit;   end; end; 

i hope asked for.