Не могу в поле edit ввести символи

[Federer]

После виполнения програми не могу ввести символи, ни букви ни цифри. Код програми:
unit TemperatureConversion;

interface

uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls;

type
TfrmTempConv = class(TForm)
lblTempData: TLabel;
edtTempData: TEdit;
btnFtoC: TButton;
btnCtoF: TButton;
memOutput: TMemo;
procedure btnFtoCClick(Sender: TObject);
procedure btnCtoFClick(Sender: TObject);

private
{ Private declarations }
public
{ Public declarations }
end;
const
DEGREE = Chr (176);
var
frmTempConv: TfrmTempConv;

implementation

{$R *.dfm}



procedure TfrmTempConv.btnFtoCClick(Sender: TObject);
var code: Integer;
degreesF: Real;
degreesC: Real;
fromF: String;
toC: String;
begin
Val (edtTempData.Text, degreesF, code);
degreesC := (5.0/9.0)*(degreesF - 32.0);
Str (degreesF:6:2, fromF);
Str (degreesC:6:2, toC);
fromF := Trim (fromF + DEGREE + 'F');
toC := Trim (toC + DEGREE + 'C');
memOutput.Lines.Add(fromF + ' äîð³âíþº ' + toC);
end;
procedure TfrmTempConv.btnCtoFClick (Sender: TObject);
var
code: Integer;
degreesF: Real;
degreesC: Real;
fromC: String;
toF: String;
begin
Val (edtTempData. Text, degreesC, code);
degreesF := 32.0 + (9.0/5.0)*degreesC;
Str (degreesF:6:2, toF);
Str (degreesC:6:2, fromC);
toF := Trim (toF + DEGREE + 'F');
fromC := Trim (fromC + DEGREE + 'C');
memOutput.Lines.Add (fromC + ' äîð³âíþº ' + toF);
end;

end.