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;

type
  TForm1 = class(TForm)
    Button1: TButton;
    GroupBox1: TGroupBox;
    Memo1: TMemo;
    Label1: TLabel;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    OpenDialog1: TOpenDialog;
    procedure Button1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  ATextFile:TextFile;
implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
 With OpenDialog1 do
  if execute then
   begin
    Label1.Caption:='当前打开的文件:'+FileName;
    if FileName<>'' then
     begin
      AssignFile(ATextFile,Opendialog1.FileName);
      ShowMessage('文件文件变量和具体的磁盘文件成功建立关联');
      Button2.Enabled:=True;
      Memo1.Lines.Clear;
     end; 
   end;
end;

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

procedure TForm1.Button2Click(Sender: TObject);
var
 TextStr:String;
begin
if MessageDlg('是否选择只读(Reset)模式打开该文本文件?',mtConfirmation,
               [mbYes, mbNo], 0) = mrYes  then
   begin
    Memo1.ReadOnly:=True;
    Button3.Enabled:=False;
   end
   else
   begin
    Memo1.ReadOnly:=False;
    Button3.Enabled:=True;
   end;
   Reset(ATextFile);
   Memo1.Lines.Clear;
   Memo1.Lines.BeginUpdate;
   try
   While Not Eof(ATextFile) do
    begin
     ReadLn(ATextFile,TextStr);
     Memo1.Lines.Add(TextStr);
    end
   finally
     Memo1.Lines.EndUpdate;
     CloseFile(ATextFile);
   end
end;

procedure TForm1.Button3Click(Sender: TObject);
var
 i:Integer;
begin
  //AssignFile(ATextFile,Opendialog1.FileName);
  Rewrite(ATextFile);
  try
  for i:=0 to Memo1.Lines.Count-1 do
   begin
    WriteLn(ATextFile,Memo1.Lines[i])
   end;
    ShowMessage('该文件已经被成功保存到磁盘上!'); 
  finally
   CloseFile(ATextFile);
  end 
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
 Close;
end;

end.