mainunit.pas

《Delphi7经典问题解析》源代码

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;
    ProgressBar1: TProgressBar;
    Label3: 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:File;
 NumRead,NumWrite:Integer;
 Buf:Array[1..2048] of byte;
begin
 AssignFile(FromFile,Opendialog1.FileName);
 Reset(FromFile,1);
 AssignFile(ToFile,SaveDialog1.FileName);
 Rewrite(ToFile,1);
 ProgressBar1.Max:=(FileSize(FromFile)*2 div sizeof(buf));
 repeat
   BlockRead(FromFile,Buf,Sizeof(Buf),NumRead);
   ProgressBar1.StepIt;
   BlockWrite(ToFile,Buf,NumRead,NumWrite);
   ProgressBar1.StepIt;
   Copying:=True;
   Application.ProcessMessages;
 until ((NumRead=0) or (NumWrite<>NumRead));
 CloseFile(FromFile);
 CloseFile(ToFile);
 Copying:=False;
 ShowMessage('复制文件过程成功完成.');  
end;

end.