unit mainunit;

interface

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

type
  TForm1 = class(TForm)
    GroupBox1: TGroupBox;
    Label1: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Label2: TLabel;
    BitBtn1: TBitBtn;
    BitBtn2: TBitBtn;
    OpenDialog1: TOpenDialog;
    SaveDialog1: TSaveDialog;
    BitBtn3: TBitBtn;
    BitBtn4: TBitBtn;
    procedure FormCreate(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
    procedure BitBtn2Click(Sender: TObject);
    procedure BitBtn4Click(Sender: TObject);
    procedure FormCloseQuery(Sender: TObject; var CanClose: Boolean);
    procedure BitBtn3Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  Copying:Boolean;
implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
begin
 OpenDialog1.FileName:='';
 OpenDialog1.InitialDir:=ExtractFileDir(Application.ExeName);
 SaveDialog1.FileName:='';
 SaveDialog1.InitialDir:=ExtractFileDir(Application.ExeName);
 BitBtn3.Enabled:=False;
 Copying:=False;
end;

procedure TForm1.BitBtn1Click(Sender: TObject);
begin
 With Opendialog1 do
  if Execute then
   Edit1.Text:=Opendialog1.FileName;
 if ((Edit1.Text<>'') and (Edit2.Text<>'')) then
   BitBtn3.Enabled:=True
 else
   BitBtn3.Enabled:=False;
end;

procedure TForm1.BitBtn2Click(Sender: TObject);
begin
 With SaveDialog1 do
  if Execute then
   Edit2.Text:=Savedialog1.FileName;
 if ((Edit1.Text<>'') and (Edit2.Text<>'')) then
   BitBtn3.Enabled:=True
 else
   BitBtn3.Enabled:=False;  
end;

procedure TForm1.BitBtn4Click(Sender: TObject);
begin
 Close;
end;

procedure TForm1.FormCloseQuery(Sender: TObject; var CanClose: Boolean);
begin
 if Copying then
  CanClose:=False
 else
  CanClose:=True;
end;

procedure TForm1.BitBtn3Click(Sender: TObject);
var
 FromFile,ToFile:TFileStream;
begin
 FromFile:=TFileStream.Create(Edit1.Text,fmOpenRead);
 try
  ToFile:=TFileStream.Create(Edit2.Text,fmCreate);
  BitBtn3.Enabled:=False;
  Copying:=True;
  try
   ToFile.CopyFrom(FromFile,0);
   ShowMessage('復制文件過程成功完成.')
  finally
   BitBtn3.Enabled:=True;
   ToFile.Free
  end
 finally
 FromFile.Free;   
 Copying:=False
 end
end;

end.