Catching improper StrToFloat values

[Traveler]

There's possibly a function for that, until then, you could write your own.
Something like:

function checkValue(text:string):boolean;
var i : byte;
begin
  result := false;
  for i := 1 to length(Text) do
  begin
    if not (text[i] in ['0'..'9','.']) then
    begin
      result := true;
      exit;
    end;
  end;
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
   if checkValue(edit1.text) then showmessage('incorrect value');
end;